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1

Demonstration Assessment of Light-Emitting Diode (LED) Freezer...  

Broader source: Energy.gov (indexed) [DOE]

Demonstration Assessment of Light-Emitting Diode (LED) Freezer Case Lighting Demonstration Assessment of Light-Emitting Diode (LED) Freezer Case Lighting This document is a report...

2

Demonstration Assessment of Light Emitting Diode (LED) Street...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Demonstration Assessment of Light Emitting Diode (LED) Street Lighting, Final Report Demonstration Assessment of Light Emitting Diode (LED) Street Lighting, Final Report This...

3

Depth of cure and compressive strength of dental composites cured with blue light emitting diodes (LEDs)  

E-Print Network [OSTI]

Depth of cure and compressive strength of dental composites cured with blue light emitting diodes with either a light emitting diode (LED) based light curing unit (LCU) or a conventional halogen LCU do reserved. Keywords: Blue light emitting diodes; Light curing unit; Composites; Irradiance; Spectrum; Depth

Ashworth, Stephen H.

4

Highly Efficient Silicon Light Emitting Diode  

E-Print Network [OSTI]

silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap

Leminh Holleman Wallinga; P. Leminh; J. Holleman; H. Wallinga

2000-01-01T23:59:59.000Z

5

Photonic crystal light emitting diode.  

E-Print Network [OSTI]

?? This master's thesis describe electromagnetic simulations of a gallium antimonide (GaSb) light emitting diode, LED. A problem for such devices is that most of… (more)

Leirset, Erlend

2010-01-01T23:59:59.000Z

6

Vehicle Traffic Control Signal Heads— Light Emitting Diode Circular Signal Supplement (VTCSH-LED). This replaced the so-called Interim LED Purchase Specifications,  

E-Print Network [OSTI]

Engineers ’ (ITE) specification for light-emitting diode (LED) circular traffic signals recently was updated (June 27, 2005) and published under the name

S. Behura

7

Demonstration Assessment of Light-Emitting Diode (LED) Accent Lighting at the Field Museum in Chicago, IL  

SciTech Connect (OSTI)

This report reviews a demonstration of light-emitting diode (LED) accent lighting compared to halogen (typical) accent lighting in a gallery of the Field Museum in Chicago, IL.

Myer, Michael; Kinzey, Bruce R.

2010-12-10T23:59:59.000Z

8

Light emitting diode color rendition properties.  

E-Print Network [OSTI]

??This paper discusses the color rendition capabilities of light emitting diodes (LEDs) and their relationship with the current standard for color rendition quality. The current… (more)

Hood, Sean

2013-01-01T23:59:59.000Z

9

Development of substrate-removal-free vertical ultraviolet light-emitting diode (RefV-LED)  

SciTech Connect (OSTI)

A vertical ultraviolet (UV) light-emitting diode (LED) that does not require substrate removal is developed. Spontaneous via holes are formed in n-AlN layer epitaxially grown on a high conductive n+Si substrate and the injected current flows directly from the p-electrode to high doped n{sup +} Si substrate through p-AlGaN, multi-quantum wells, n-AlGaN and spontaneous via holes in n-AlN. The spontaneous via holes were formed by controlling feeding-sequence of metal-organic gas sources and NH{sub 3} and growth temperature in MOCVD. The via holes make insulating n-AlN to be conductive. We measured the current-voltage, current-light intensity and emission characteristics of this device. It exhibited a built-in voltage of 3.8 V and emission was stated at 350 nm from quantum wells with successive emission centered at 400?nm. This UV LED can be produced, including formation of n and p electrodes, without any resist process.

Kurose, N., E-mail: kurose@fc.ritsumei.ac.jp; Aoyagi, Y. [The Research Organization of Science and Technology, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577 (Japan)] [The Research Organization of Science and Technology, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577 (Japan); Shibano, K.; Araki, T. [Department of Science and Technology, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577 (Japan)] [Department of Science and Technology, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577 (Japan)

2014-02-15T23:59:59.000Z

10

Demonstration Assessment of Light-Emitting Diode (LED) Parking Lot Lighting in Leavenworth, KS  

SciTech Connect (OSTI)

This report describes the process and results of a demonstration of solid-state lighting (SSL) technology in a commercial parking lot lighting application, under the U.S. Department of Energy (DOE) Solid-State Lighting Technology GATEWAY Demonstration Program. The parking lot is for customers and employees of a Walmart Supercenter in Leavenworth, Kansas and this installation represents the first use of the LED Parking Lot Performance Specification developed by the DOE’s Commercial Building Energy Alliance. The application is a parking lot covering more than a half million square feet, lighted primarily by light-emitting diodes (LEDs). Metal halide wall packs were installed along the building facade. This site is new construction, so the installed baseline(s) were hypothetical designs. It was acknowledged early on that deviating from Walmart’s typical design would reduce the illuminance on the site. Walmart primarily uses 1000W pulse-start metal halide (PMH) lamps. In order to provide a comparison between both typical design and a design using conventional luminaires providing a lower illuminance, a 400W PMH design was also considered. As mentioned already, the illuminance would be reduced by shifting from the PMH system to the LED system. The Illuminating Engineering Society of North America (IES) provides recommended minimum illuminance values for parking lots. All designs exceeded the recommended illuminance values in IES RP-20, some by a wider margin than others. Energy savings from installing the LED system compared to the different PMH systems varied. Compared to the 1000W PMH system, the LED system would save 63 percent of the energy. However, this corresponds to a 68 percent reduction in illuminance as well. In comparison to the 400W PMH system, the LED system would save 44 percent of the energy and provide similar minimum illuminance values at the time of relamping. The LED system cost more than either of the PMH systems when comparing initial costs. However, when the life-cycle costs from energy and maintenance were factored into the scenario, the LED system had lower costs at the end of a 10-year analysis period. The LED system had a 6.1 year payback compared to the 1000W PMH system and a 7.5 year payback versus the 400W PMH system. The costs reflect high initial cost for the LED luminaire, plus more luminaires and (subsequently) more poles for the LED system. The other major issue affecting cost effectiveness was that Leavenworth, Kansas has very low electricity costs. The melded rate for this site was $0.056 per kWh for electricity. However, if the national electricity rate of $0.1022/kWh was used the payback would change to between four and five years for the LED system. This demonstration met the GATEWAY requirements of saving energy, matching or improving illumination, and being cost effective. The project also demonstrated that the Commercial Building Energy Alliance (CBEA) specification works in practice. Walmart appreciated having an entire site lighted by LEDs to gain more experience with the technology. Walmart is reviewing the results of the demonstration as they consider their entire real estate portfolio.

Myer, Michael; Kinzey, Bruce R.; Curry, Ku'uipo

2011-05-06T23:59:59.000Z

11

Thermal pumping of light-emitting diodes  

E-Print Network [OSTI]

The work presented here is a study of thermally enhanced injection in light-emitting diodes (LEDs). This effect, which we refer to as "thermal pumping", results from Peltier energy exchange from the lattice to charge ...

Gray, Dodd (Dodd J.)

2011-01-01T23:59:59.000Z

12

Quantum Dot Light Emitting Diode  

SciTech Connect (OSTI)

The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

Keith Kahen

2008-07-31T23:59:59.000Z

13

Quantum Dot Light Emitting Diode  

SciTech Connect (OSTI)

The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

Kahen, Keith

2008-07-31T23:59:59.000Z

14

Broadband light-emitting diode  

DOE Patents [OSTI]

A broadband light-emitting diode. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3-2 .mu.m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-division-multiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft.

Fritz, Ian J. (Albuquerque, NM); Klem, John F. (Sandia Park, NM); Hafich, Michael J. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

15

Broadband light-emitting diode  

DOE Patents [OSTI]

A broadband light-emitting diode is disclosed. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3--2 {micro}m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-divisionmultiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft. 10 figs.

Fritz, I.J.; Klem, J.F.; Hafich, M.J.

1998-07-14T23:59:59.000Z

16

Water Cooling of High Power Light Emitting Diode Henrik Srensen  

E-Print Network [OSTI]

Water Cooling of High Power Light Emitting Diode Henrik Sørensen Department of Energy Technology and product lifetime. The high power Light Emitting Diodes (LED) belongs to the group of electronics

Berning, Torsten

17

White light emitting diode as liquid crystal display backlight ; High brightness light emitting diode as liquid crystal display backlight .  

E-Print Network [OSTI]

??The discovery of high brightness (white) light emitting diode (LED) is considered as a real threat to the current lighting industry in various applications. One… (more)

Soon, Chian Myau

2007-01-01T23:59:59.000Z

18

Demonstration Assessment of Light-Emitting Diode (LED) Retrofit Lamps at the Lobby of the Bonneville Power Administration, Portland, OR  

SciTech Connect (OSTI)

This report describes the process and results of a demonstration of solid-state lighting (SSL) technology in the lobby of the Bonneville Power Administration (BPA) headquarters building in Portland, Oregon. The project involved a simple retrofit of 32 track lights used to illuminate historical black-and-white photos and printed color posters from the 1930s and 1940s. BPA is a federal power marketing agency in the Northwestern United States, and selected this prominent location to demonstrate energy efficient light-emitting diode (LED) retrofit options that not only can reduce the electric bill for their customers but also provide attractive alternatives to conventional products, in this case accent lighting for BPA's historical artwork.

Miller, Naomi

2011-07-01T23:59:59.000Z

19

Demonstration Assessment of Light-Emitting Diode (LED) Street Lighting Host Site: Lija Loop, Portland, Oregon  

SciTech Connect (OSTI)

This report describes the process and results of a demonstration of solid-state lighting (SSL) technology in a residential street lighting application, under the U.S. Department of Energy GATEWAY Solid-State Lighting Technology Demonstration Program. In this project, eight 100W (nominal) high-pressure sodium cobra head fixtures were replaced with a like number of LED street light luminaires manufactured by Leotek, Inc. The Leotek product achieved an estimated payback in the Lija Loop installation of about 20 years for replacement scenarios and a much shorter 7.6 years for new installations. Much of the associated energy savings (55%) supporting these payback periods, however, were achieved by reducing average horizontal photopic illuminance a similar amount (53%). Examined from a different perspective, the measured performance suggests that the Leotek product is at approximate parity with the HPS cobra head in terms of average delivered photopic illumination for a given power consumption. HPS comprises the second most efficacious street lighting technology available, exceeded only by low pressure sodium (LPS). LPS technology is not considered suitable for most street lighting applications due to its monochromatic spectral output and poor color rendering ability; therefore, this LED product is performing at an efficiency level comparable to its primary competition in this application.

Kinzey, Bruce R.; Myer, Michael

2009-11-01T23:59:59.000Z

20

White light emitting diode as liquid crystal display backlight  

E-Print Network [OSTI]

The discovery of high brightness (white) light emitting diode (LED) is considered as a real threat to the current lighting industry in various applications. One of the most promising sectors would be using white LED to ...

Soon, Chian Myau

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Thermo-electrically pumped semiconductor light emitting diodes  

E-Print Network [OSTI]

Thermo-electric heat exchange in semiconductor light emitting diodes (LEDs) allows these devices to emit optical power in excess of the electrical power used to drive them, with the remaining power drawn from ambient heat. ...

Santhanam, Parthiban

2014-01-01T23:59:59.000Z

22

E-Print Network 3.0 - algainp light-emitting diodes Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by sequentially adding components of different types. Six hundred AlGaInP GaAs light- emitting diode segments... of 600 AlGaInP GaAs light-emitting diodes (LEDs) onto device...

23

Multispectral imaging of the ocular fundus using light emitting diode illumination  

E-Print Network [OSTI]

Multispectral imaging of the ocular fundus using light emitting diode illumination N. L. Everdell,1 on light emitting diode LED illumination that produces multispectral optical images of the human ocular

Claridge, Ela

24

Demonstration Assessment of Light Emitting Diode (LED) Commercial Garage Lights In the Providence Portland Medical Center, Portland, Oregon  

SciTech Connect (OSTI)

This U.S. Department of Energy GATEWAY Demonstration project studied the applicability of light-emitting diode (LED) luminaires for commercial parking garage applications. High-pressure sodium (HPS) area luminaires were replaced with new LED area luminaires. The project was supported under the U.S. Department of Energy (DOE) Solid State Lighting Program. Other participants in the demonstration project included Providence Portland Medical Center in Portland, Oregon, the Energy Trust of Oregon, and Lighting Sciences Group (LSG) Inc. Pacific Northwest National Laboratory (PNNL) conducted the measurements and analysis of the results. PNNL manages GATEWAY demonstrations for DOE and represents their perspective in the conduct of the work. Quantitative and qualitative measurements of light and electrical power were taken at the site for both HPS and LED light sources. Economic costs were estimated and garage users’ responses to the new light sources were gauged with a survey. Six LED luminaires were installed in the below-ground parking level A, replacing six existing 150W HPS lamps spread out over two rows of parking spaces. Illuminance measurements were taken at floor level approximately every 4 ft on a 60-ft x 40-ft grid to measure light output of these LED luminaires which were termed the “Version 1” luminaires. PNNL conducted power measurements of the circuit in the garage to which the 6 luminaires were connected and determined that they drew an average of 82 W per lamp. An improved LED luminaire, Version 2, was installed in Level B of the parking garage. Illuminance measurements were not made of this second luminaire on site due to higher traffic conditions, but photometric measurements of this lamp and Version 1 were made in an independent testing laboratory and power usage for Version 2 was also measured. Version 1 was found to produce 3600 lumens and Version 2 was found to produce 4700 lumens of light and to consume 78 Watts. Maximum and minimum light levels were measured for the HPS and LED Version 1 luminaires and projected for the Version 2 luminaires. Maximum light levels were 23.51 foot candles, 20.54 fc, and 26.7 fc respectively and minimum light levels were 1.49 fc, 1.45 fc, and 1.88 fc. These results indicate very similar or even slightly higher light levels produced by the LED lamps, despite the higher lumen output of the HPS lamp. The LED lamps provide higher luminaire efficacy because all of the light is directed down and out. None of it is “lost” in the fixture. Also the HPS luminaire had poorly designed optics and a plastic covering that tended to get dirty and cracked, further decreasing the realized light output.[is this an accurate way to say this?] Consumer perceptions of the Version 2 LED were collected via a written survey form given to maintenance and security personnel. More than half felt the LED luminaires provided more light than the HPS lamps and a majority expressed a preference for the new lamps when viewing the relamped area through a security camera. Respondents commented that the LED luminaires were less glary, created less shadows, had a positive impact on visibility, and improved the overall appearance of the area. PNNL conducted an economic analysis and found that the Version 1 lamp produced annual energy savings of 955 kWh and energy cost savings of $76.39 per lamp at electricity rates of 6.5 cents per kWh and $105.03 at 11 cents per kWh. PNNL found that the Version 2 lamp produced annual energy savings of 991 kWh and energy cost savings of $79.26 per lamp at electricity rates of 6.5 cents per kWh and $108.98 at 11 cents per kWh. PNNL also calculated simple payback and found that Version 1 showed paybacks of 5.4 yrs at 6.5c/kWh and 4.1 yrs at 11c/kWh while Version 2 showed paybacks of 5.2 yrs at 6.5c/kWh and 3.9 yrs at 11c/kWh.

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

2008-11-11T23:59:59.000Z

25

Highly Efficient Silicon Light Emitting Diode  

E-Print Network [OSTI]

In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a local strain field that is formed by dislocation loop arrays. The dependence of device electroluminescent properties on the annealing conditions is carefully examined as a high temperature process has profound influence on these dislocations. Increased luminescent intensity at higher device temperature, together with pure diffusion current conduction mechanism evidently shows the influence of the dislocation loops. The electrical properties of the diode are reasonable with low leakage reverse current.

Leminh Holleman Wallinga; P. Leminh; J. Holleman; H. Wallinga

2000-01-01T23:59:59.000Z

26

Vertical Pillar-Superlattice Array and Graphene Hybrid Light Emitting Diodes  

E-Print Network [OSTI]

Vertical Pillar-Superlattice Array and Graphene Hybrid Light Emitting Diodes Jung Min Lee, Jae a class of light emitting diode (LED) with interesting mechanical, optical, and electrical characteristics, light-emitting diodes, 3D architectures, transparent electrodes V ertical arrays of one-dimensional (1D

Rogers, John A.

27

Coupled optical and electronic simulations of electrically pumped photonic-crystal-based light-emitting diodes  

E-Print Network [OSTI]

trade-offs in electrically pumped photonic-crystal-based light-emitting diodes. A finite- toelectronic devices, such as light-emitting diodes LEDs and lasers. It has been suggested that a thin slabCoupled optical and electronic simulations of electrically pumped photonic-crystal-based light-emitting

Dutton, Robert W.

28

Wire-shaped semiconductor light-emitting diodes for general-purpose lighting  

SciTech Connect (OSTI)

The object of this work is to develop and optimize a new type of light-emitting diode (LED) with a wire-shaped, cylindrical geometry.

Mauk, Michael G.

2002-10-28T23:59:59.000Z

29

Shelf life of five meat products displayed under light emitting diode or fluorescent lighting.  

E-Print Network [OSTI]

??Light emitting diode (LED) and fluorescent (FLS) lighting effects on enhanced pork loin chops, beef longissimus dorsi and semimembranosus steaks, ground beef, and ground turkey… (more)

Steele, Kyle Stover

2011-01-01T23:59:59.000Z

30

spectroscopic techniques A Multi-Source Portable Light Emitting Diode Spectrofluorometer  

E-Print Network [OSTI]

spectroscopic techniques A Multi-Source Portable Light Emitting Diode Spectrofluorometer SAFWAN only 1.5 kg that uses multiple light emitting diodes (LEDs) as excitation sources was developed emitting diodes; LEDs; Animal forage; Excitation-emission matrices; EEM. INTRODUCTION Movement of chemical

31

High-Performance Organic Light-Emitting Diodes Using ITO  

E-Print Network [OSTI]

High-Performance Organic Light-Emitting Diodes Using ITO Anodes Grown on Plastic by Room,* Mark E. Madsen, Antonio DiVenere, and Seng-Tiong Ho Organic light-emitting diodes (OLEDs) fabricated

Ho, Seng-Tiong

32

Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract--Semiconductor nanocrystal quantum dots (NQD)  

E-Print Network [OSTI]

Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract-- Semiconductor nanocrystal convertors integrated on light-emitting diodes (LEDs). The use of nonradiative energy transfer, also known-LEDs for lighting applications. Index Terms-- Förster resonance energy transfer, light emitting diode, nanocrystal

Demir, Hilmi Volkan

33

Demonstration Assessment of Light Emitting Diode (LED) Walkway Lighting at the Federal Aviation Administration William J. Hughes Technical Center, in Atlantic City, New Jersey  

SciTech Connect (OSTI)

This report documents the results of a collaborative project to demonstrate a solid state lighting (SSL) general illumination product in an outdoor area walkway application. In the project, six light-emitting diode (LED) luminaires were installed to replace six existing high pressure sodium (HPS) luminaires mounted on 14-foot poles on a set of exterior walkways and stairs at the Federal Aviation Administration (FAA) William J. Hughes Technical Center in Atlantic City, New Jersey, during December, 2007. The effort was a U.S. Department of Energy (DOE) SSL Technology Gateway Demonstration that involved a collaborative teaming agreement between DOE, FAA and Ruud Lighting (and their wholly owned division, Beta LED). Pre- and post-installation power and illumination measurements were taken and used in calculations of energy savings and related economic payback, while personnel impacted by the new lights were provided questionnaires to gauge their perceptions and feedback. The SSL product demonstrated energy savings of over 25% while maintaining illuminance levels and improving illuminance uniformity. PNNL's economic analysis yielded a variety of potential payback results depending on the assumptions used. In the best case, replacing HPS with the LED luminaire can yield a payback as low as 3 years. The new lamps were quite popular with the affected personnel, who gave the lighting an average score of 4.46 out of 5 for improvement.

Kinzey, Bruce R.; Myer, Michael

2008-03-18T23:59:59.000Z

34

A strategy for the use of light emitting diodes by autonomous underwater vehicles  

E-Print Network [OSTI]

Light Emitting Diode (LED) technology has advanced dramatically in a few short years. An expensive and difficult to manufacture LED array containing nearly 100 individual LEDs and measuring at least 5 cm² can now be replaced ...

Curran, Joseph R. (Joseph Robinson)

2004-01-01T23:59:59.000Z

35

Flip-chip light emitting diode with resonant optical microcavity  

SciTech Connect (OSTI)

A flip-chip light emitting diode with enhanced efficiency. The device structure employs a microcavity structure in a flip-chip configuration. The microcavity enhances the light emission in vertical modes, which are readily extracted from the device. Most of the rest of the light is emitted into waveguided lateral modes. Flip-chip configuration is advantageous for light emitting diodes (LEDs) grown on dielectric substrates (e.g., gallium nitride LEDs grown on sapphire substrates) in general due to better thermal dissipation and lower series resistance. Flip-chip configuration is advantageous for microcavity LEDs in particular because (a) one of the reflectors is a high-reflectivity metal ohmic contact that is already part of the flip-chip configuration, and (b) current conduction is only required through a single distributed Bragg reflector. Some of the waveguided lateral modes can also be extracted with angled sidewalls used for the interdigitated contacts in the flip-chip configuration.

Gee, James M.; Bogart, Katherine H.; Fischer, Arthur J.

2005-11-29T23:59:59.000Z

36

Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting on Residential and Commercial Streets in Palo Alto, CA  

SciTech Connect (OSTI)

This report is part of a GATEWAY demonstration that replaced existing HPS streetlights with two different types of LED products and one induction product. Energy savings ranged from 6% to 44%.

Myer, Michael; Kinzey, Bruce R.; Tam, Christine

2010-06-24T23:59:59.000Z

37

Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting at the I-35W Bridge, Minneapolis, MN  

SciTech Connect (OSTI)

This report describes the process and results of a demonstration of solid-state lighting (SSL) technology conducted in 2009 at the recently reconstructed I-35W bridge in Minneapolis, MN. The project was supported under the U.S. Department of Energy (DOE) Solid-State Lighting GATEWAY Technology Demonstration Program. Other participants in the demonstration project included the Minnesota Department of Transportation (Mn/DOT), Federal Highways Administration (FHWA), and BetaLED™ (a division of Ruud Lighting). Pacific Northwest National Laboratory (PNNL) conducted the measurements and analysis of the results. DOE has implemented a three-year evaluation of the LED luminaires in this installation in order to develop new longitudinal field data on LED performance in a challenging, real-world environment. This document provides information through the initial phase of the I-35W bridge project, up to and including the opening of the bridge to the public and the initial feedback received on the LED lighting installation from bridge users. Initial findings of the evaluation are favorable, with minimum energy savings level of 13% for the LED installation relative to the simulated base case using 250W high-pressure sodium (HPS) fixtures. The LEDs had an average illuminance level of 0.91 foot candles compared to 1.29 fc for the HPS lamps. The LED luminaires cost $38,000 more than HPS lamps, yielding a lengthy payback period, however the bridge contractor had offered to include the LED luminaires as part of the construction package at no additional cost. One potentially significant benefit of the LEDs in this installation is avoiding rolling lane closures on the heavily-traveled interstate bridge for the purpose of relamping the HPS fixtures. Rolling lane closures involve multiple crew members and various maintenance and safety vehicles, diversion of traffic, as well as related administrative tasks (e.g., approvals, scheduling, etc.). Mn/DOT records show an average cost of relamping fixtures along interstate roadways of between $130-150 per pole. The previous bridge saw a lamp mortality rate of approximately 50% every two years, though the new bridge was designed to minimize many of the vibration issues. A voluntary Web-based feedback survey of nearly 500 self-described bridge users showed strong preference for the LED lighting - positive comments outnumbered negative ones by about five-to-one.

Kinzey, Bruce R.; Myer, Michael

2009-08-31T23:59:59.000Z

38

Efficiency enhancement in a light-emitting diode with a two-dimensional surface grating photonic crystal  

E-Print Network [OSTI]

Efficiency enhancement in a light-emitting diode with a two-dimensional surface grating photonic 21 November 2003 We demonstrate a light-emitting diode exhibiting 1.7­2.7-fold enhancement in light light emitting diode LED , the ef- ficiency is limited to several percents by a low light extrac- tion

Baba, Toshihiko

39

Poly (p-phenyleneacetylene) light-emitting diodes  

DOE Patents [OSTI]

Acetylene containing poly(p-phenyleneacetylene) (PPA) - based light-emitting diodes (LEDs) are provided. The LEDs are fabricated by coating a hole-injecting electrode, preferably an indium tin oxide (ITO) coated glass substrate, with a PPA polymer, such as a 2,5-dibutoxy or a 2,5-dihexoxy derivative of PPA, dissolved in an organic solvent. This is then followed by evaporating a layer of material capable of injecting electrons, such as Al or Al/Ca, onto the polymer to form a base electrode. This composition is then annealed to form efficient EL diodes. 8 figs.

Shinar, J.; Swanson, L.S.; Lu, F.; Ding, Y.; Barton, T.J.; Vardeny, Z.V.

1994-10-04T23:59:59.000Z

40

Fabrication of poly(p-phenyleneacetylene) light-emitting diodes  

DOE Patents [OSTI]

Acetylene-containing poly(p-phenyleneacetylene) (PPA)-based light-emitting diodes (LEDs) are provided. The LEDs are fabricated by coating a hole-injecting electrode, preferably an indium tin oxide (ITO) coated glass substrate, with a PPA polymer, such as a 2,5-dibutoxy or a 2,5-dihexoxy derivative of PPA, dissolved in an organic solvent. This is then followed by evaporating a layer of material capable of injecting electrons, such as Al or Al/Ca, onto the polymer to form a base electrode. This composition is then annealed to form efficient EL diodes. 8 figs.

Shinar, J.; Swanson, L.S.; Lu, F.; Ding, Y.

1994-08-02T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Poly (p-phenyleneneacetylene) light-emitting diodes  

DOE Patents [OSTI]

Acetylene containing poly(p-phenyleneacetylene) (PPA) - based light-emitting diodes (LEDs) are provided. The LEDs are fabricated by coating a hole-injecting electrode, preferably an indium tin oxide (ITO) coated glass substrate, with a PPA polymer, such as a 2,5-dibutoxy or a 2,5-dihexoxy derivative of PPA, dissolved in an organic solvent. This is then followed by evaporating a layer of material capable of injecting electrons, such as Al or Al/Ca, onto the polymer to form a base electrode. This composition is then annealed to form efficient EL diodes.

Shinar, Joseph (Ames, IA); Swanson, Leland S. (Ames, IA); Lu, Feng (Ames, IA); Ding, Yiwei (Ames, IA); Barton, Thomas J. (Ames, IA); Vardeny, Zeev V. (Salt Lake City, UT)

1994-10-04T23:59:59.000Z

42

Fabrication of poly(p-phenyleneacetylene) light-emitting diodes  

DOE Patents [OSTI]

Acetylene containing poly(p-phenyleneacetylene) (PPA) - based light-emitting diodes (LEDs) are provided. The LEDs are fabricated by coating a hole-injecting electrode, preferably an indium tin oxide (ITO) coated glass substrate, with a PPA polymer, such as a 2,5-dibutoxy or a 2,5-dihexoxy derivative of PPA, dissolved in an organic solvent. This is then followed by evaporating a layer of material capable of injecting electrons, such as A1 or A1/Ca, onto the polymer to form a base electrode. This composition is then annealed to form efficient EL diodes.

Shinar, Joseph (Ames, IA); Swanson, Leland S. (Ames, IA); Lu, Feng (Ames, IA); Ding, Yiwei (Ames, IA)

1994-08-02T23:59:59.000Z

43

Genetic algorithms used for the optimization of light-emitting diodes and solar thermal collectors  

E-Print Network [OSTI]

Genetic algorithms used for the optimization of light-emitting diodes and solar thermal collectors developed for the optimization of light-emitting diodes (LED) and solar thermal collectors. The surface a light-extraction efficiency of only 3.7%). The solar thermal collector we considered consists

Mayer, Alexandre

44

Demonstration Assessment of Light Emitting Diode (LED) Residential Downlights and Undercabinet Lights in the Lane County Tour of Homes, Eugene, Oregon  

SciTech Connect (OSTI)

In August 2008 the Pacific Northwest National Laboratory (PNNL) conducted a light emitting diode (LED) residential lighting demonstration project for the U.S. Department of Energy (DOE), Office of Building Technologies, as part of DOE’s Solid State Lighting (SSL) Technology Demonstration Gateway Program. Two lighting technologies, an LED replacement for downlight lamps (bulbs) and an LED undercabinet lighting fixture, were tested in the demonstration which was conducted in two homes built for the 2008 Tour of Homes in Eugene, Oregon. The homes were built by the Lane County Home Builders Association (HBA), and Future B Homes. The Energy Trust of Oregon (ETO) also participated in the demonstration project. The LED downlight product, the LR6, made by Cree LED Lighting Solutions acts as a screw-in replacement for incandescent and halogen bulbs in recessed can downlights. The second product tested is Phillips/Color Kinetics’ eW® Profile Powercore undercabinet fixture designed to mount under kitchen cabinets to illuminate the countertop and backsplash surfaces. Quantitative and qualitative measurements of light performance and electrical power usage were taken at each site before and after initially installed halogen and incandescent lamps were replaced with the LED products. Energy savings and simple paybacks were also calculated and builders who toured the homes were surveyed for their responses to the LED products. The LED downlight product drew 12 Watts of power, cutting energy use by 82% compared to the 65W incandescent lamp and by 84% compared to the 75W halogen lamp. The LED undercabinet fixture drew 10 watts, cutting energy use by 83% to 90% compared to the halogen product, which was tested at two power settings: a low power 60W setting and a high power 105W setting. The LED downlight consistently provided more light than the halogen and incandescent lamps in horizontal measurements at counter height and floor level. It also outperformed in vertical illuminance measurements taken on the walls, indicating better lateral dispersion of the light. The undercabinet fixture’s light output was midway between the low and high power halogen undercabinet fixture light outputs (35.8 foot candle versus 13.4 fc and 53.4 fc) but it produced a more uniform light (max/min ratio of 7.0 versus 10.8). The color correlated temperature (CCT, the blue or yellowness) of the LED light correlated well with the halogen and incandescent lights (2675 K vs 2700 K). The color rendering of the LED downlight also correlated well at 92 CRI compared to 100 CRI for the halogen and incandescent lamps. The LED undercabinet fixture had measures of 2880 K CCT and 71 CRI compared to the 2700 K and 100 CRI scores for the halogen undercabinet fixture. Builders who toured the homes were surveyed; they gave the LED downlight high marks for brightness, said the undercabinet improved shadows and glare and said both products improved overall visibility, home appearance, and home value. Paybacks on the LED downlight ranged from 7.6 years (assuming electricity cost of 11 c/kWh) to 13.5 years (at 5C/kWh). Paybacks on the LED undercabinet fixture in a new home ranged from 4.4 years (11c/kWh electricity) to 7.6 years (5c/kWh) based on product costs of $95 per LED downlight and $140 per LED undercabinet fixture at 3 hrs per day of usage for the downlight and 2 hrs per day for the undercabinet lighting.

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

2008-11-10T23:59:59.000Z

45

Organic-Inorganic Hetero Junction White Light Emitting Diode.  

E-Print Network [OSTI]

?? The purpose of this thesis work is to design and fabricates organic-inorganic hetero junction White Light Emitting Diode (WLED). In this WLED, inorganic material… (more)

Lubuna Beegum, Shafeek

2008-01-01T23:59:59.000Z

46

Thickness-dependent changes in the optical properties of PPV-and PF-based polymer light emitting diodes  

E-Print Network [OSTI]

the thickness-dependent optical properties of single layer polymer light emitting diodes for two materials, poly the electronic and optical properties of these materials in light emitting diode LED structures.2 OurThickness-dependent changes in the optical properties of PPV- and PF-based polymer light emitting

Carter, Sue

47

Junction temperature, spectral shift, and efficiency in GaInN-based blue and green light emitting diodes  

E-Print Network [OSTI]

Keywords: GaInN/GaN Light emitting diode temperature Micro-Raman Photoluminescence Electroluminescence well light emitting diode (LED) dies is analyzed by micro-Raman, photoluminescence, cathodoluminescenceJunction temperature, spectral shift, and efficiency in GaInN-based blue and green light emitting

Wetzel, Christian M.

48

High efficiency III-nitride light-emitting diodes  

DOE Patents [OSTI]

Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

2013-05-28T23:59:59.000Z

49

The Effect of Light Emitting Diode Phototherapy on the Rate of Orthodontic Tooth Movement - A Clinical Study.  

E-Print Network [OSTI]

??Increasing the rate of orthodontic tooth movement (OTM) can reduce risks such as periodontal disease and caries. This study investigated whether light emitting diode (LED)… (more)

Chung, Sean

2013-01-01T23:59:59.000Z

50

Room-temperature direct bandgap electroluminesence from Ge-on-Si light-emitting diodes  

E-Print Network [OSTI]

We report what we believe to be the first demonstration of direct bandgap electroluminescence (EL) from Ge/Si heterojunction light-emitting diodes (LEDs) at room temperature. In-plane biaxial tensile strain is used to ...

Sun, Xiaochen

51

Colloidal semiconductor nanocrystals as nanoscale emissive probes in light emitting diodes and cell biology  

E-Print Network [OSTI]

This thesis employs colloidal semiconductor nanocrystals (NCs) as nanoscale emissive probes to investigate the physics of light emitting diodes (LEDs), as well as to unveil properties of cells that conventional imaging ...

Huang, Hao, Ph. D. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

52

Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes  

E-Print Network [OSTI]

Saturated and tunable emission colors make colloidal quantum-dot light-emitting diodes (QD-LEDs) interesting for the next generation of display and lighting technologies. However, there still remain various hurdles to the ...

Shirasaki, Yasuhiro

2013-01-01T23:59:59.000Z

53

Development of ZnO Based Light Emitting Diodes and Laser Diodes.  

E-Print Network [OSTI]

??ZnO based homojunction light emitting diode, double heterojunction light emitting diode, embedded heterojunction random laser diode and Fabry-Perot nanowire laser devices were fabricated and characterized.… (more)

Kong, Jieying

2012-01-01T23:59:59.000Z

54

Microcavity enhanced vertical-cavity light-emitting diodes U. Keller, G. R. Jacobovitz-Veselka, J. E. Cunningham, W. Y. Jan, B. Tell,  

E-Print Network [OSTI]

Microcavity enhanced vertical-cavity light-emitting diodes U. Keller, G. R. Jacobovitz-Veselka, J-cavity light-emitting diode (LED) by continuously changing the microcavity resonance with respect for optical interconnects seems to be the light emitting diode (LED), or better yet, the microcavity en

Keller, Ursula

55

Conference 5739, SPIE International Symposium Integrated Optoelectronic Devices, 22-27 Jan 2005, San Jose, CA Development of high power green light emitting diode dies in  

E-Print Network [OSTI]

, San Jose, CA Development of high power green light emitting diode dies in piezoelectric Ga in green light emitting diodes is one of the big challenges towards all-solid- state lighting. The prime,3], and commercialization [4,5] of high brightness light emitting diodes LEDs has led to a 1.82 Billion-$/year world market

Wetzel, Christian M.

56

A micrometer-size movable light emitting area in a resonant tunneling light emitting diode  

SciTech Connect (OSTI)

We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30??m for a bias increment of 0.2?V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patanè, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)] [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)

2013-12-09T23:59:59.000Z

57

High power light emitting diode based setup for photobleaching fluorescent impurities  

E-Print Network [OSTI]

High power light emitting diode based setup for photobleaching fluorescent impurities Tobias K be photobleached before final sample preparation. The instrument consists of high power light emitting diodes

Kaufman, Laura

58

Diffusion injected multi-quantum well light-emitting diode structure  

SciTech Connect (OSTI)

The attention towards light-emitting diode (LED) structures based on nanowires, surface plasmon coupled LEDs, and large-area high-power LEDs has been increasing for their potential in increasing the optical output power and efficiency of LEDs. In this work we demonstrate an alternative way to inject charge carriers into the active region of an LED, which is based on completely different current transport mechanism compared to conventional current injection approaches. The demonstrated structure is expected to help overcoming some of the challenges related to current injection with conventional structures. A functioning III-nitride diffusion injected light-emitting diode structure, in which the light-emitting active region is located outside the pn-junction, is realized and characterized. In this device design, the charge carriers are injected into the active region by bipolar diffusion, which could also be utilized to excite otherwise challenging to realize light-emitting structures.

Riuttanen, L., E-mail: lauri.riuttanen@aalto.fi; Nykänen, H.; Svensk, O.; Suihkonen, S.; Sopanen, M. [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland); Kivisaari, P.; Oksanen, J.; Tulkki, J. [Department of Biomedical Engineering and Computational Science, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)

2014-02-24T23:59:59.000Z

59

White organic light-emitting diodes: Status and perspective  

E-Print Network [OSTI]

White organic light-emitting diodes (OLEDs) are ultrathin, large-area light sources made from organic semiconductor materials. Over the past decades, much research has been spent on finding suitable materials to realize ...

Reineke, Sebastian

60

Mid-ultraviolet light-emitting diode detects dipicolinic acid.  

SciTech Connect (OSTI)

Dipicolinic acid (DPA, 2,6-pyridinedicarboxylic acid) is a substance uniquely present in bacterial spores such as that from anthrax (B. anthracis). It is known that DPA can be detected by the long-lived fluorescence of its terbium chelate; the best limit of detection (LOD) reported thus far using a large benchtop gated fluorescence instrument using a pulsed Xe lamp is 2 nM. We use a novel AlGaN light-emitting diode (LED) fabricated on a sapphire substrate that has peak emission at 291 nm. Although the overlap of the emission band of this LED with the absorption band of Tb-DPA ({lambda}{sub max} doublet: 273, 279 nm) is not ideal, we demonstrate that a compact detector based on this LED and an off-the-shelf gated photodetection module can provide an LOD of 0.4 nM, thus providing a basis for convenient early warning detectors.

Bogart, Katherine Huderle Andersen; Lee, Stephen Roger; Temkin, Henryk (Texas Tech University, Lubbock, TX); Crawford, Mary Hagerott; Dasgupta, Purnendu K. (Texas Tech University, Lubbock, TX); Li, Qingyang (Texas Tech University, Lubbock, TX); Allerman, Andrew Alan; Fischer, Arthur Joseph

2005-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

C. Wetzel et al MRS Internet J. Nitride Semicond. Res. 10, 2 (2005) 1 Development of High Power Green Light Emitting Diode Chips  

E-Print Network [OSTI]

Power Green Light Emitting Diode Chips C. Wetzel and T. Detchprohm Future Chips Constellation Abstract The development of high emission power green light emitting diodes chips using GaInN/GaN multi production-scale implementation of this green LED die process. Keywords: nitrides, light emitting diode

Wetzel, Christian M.

62

TRICOLOR LIGHT EMITTING DIODE DOT MATRIX DISPLAY SYSTEM WITHAUDIO OUTPUT  

E-Print Network [OSTI]

1 TRICOLOR LIGHT EMITTING DIODE DOT MATRIX DISPLAY SYSTEM WITHAUDIO OUTPUT Grantham Pang, Chi emitting diodes; tricolor display; audio communication. I. Introduction This paper relates to a tricolor broadcasting through the visible light rays transmitted by the display panel or assembly. Keywords: light

Pang, Grantham

63

White Light Emitting Diode Development for General Illumination Applications  

SciTech Connect (OSTI)

This report contains a summary of technical achievements during a 3-year project aimed at developing the chip and packaging technology necessary to demonstrate efficient, high flux light-emitting diode (LED) arrays using Cree's gallium nitride/silicon carbide (GaN/SiC) LED technology as the starting point. Novel chip designs and fabrication processes are described that led to high power blue LEDs that achieved 310 mW of light output at 350 mA drive current, corresponding to quantum and wall plug efficiencies of 32.5% and 26.5%, respectively. When combined with phosphor, high power white LEDs with luminous output of 67 lumens and efficacy of 57 lumens per watt were also demonstrated. Advances in packaging technology are described that enabled compact, multi-chip white LED lamp modules with 800-1000 lumens output at efficacies of up to 55 lumens per watt. Lamp modules with junction-to-ambient thermal resistance as low as 1.7 C/watt have also been demonstrated.

James Ibbetson

2006-05-01T23:59:59.000Z

64

City of Phildelphia: Light emitting diodes for traffic signal displays  

SciTech Connect (OSTI)

This project investigated the feasibility of using light emitting diodes (LEDs) for red traffic signals in a demonstration program at 27 signalized intersections in the City of Philadelphia. LED traffic signals have the potential to achieve significant savings over standard incandescent signals in terms of energy usage and costs, signal relamping costs, signal system maintenance costs, tort liability, and environmental impact. Based on successful experience with the demonstration program, the City of Philadelphia is currently developing funding for the conversion of all existing red incandescent traffic signals at approximately 2,700 intersections to LED signals. This program is expected to cost approximately $4.0 million and save about $850,000 annually in energy costs. During late 1993 and early 1994, 212 red LED traffic signals (134 8-inch signals and 78 12-inch signals) were installed at 27 intersections in Philadelphia. The first group of 93 signals were installed at 13 prototypical intersections throughout the City. The remaining group of signals were installed on a contiguous route in West Philadelphia consisting of standard incandescent signals and LED signals interspersed in a random pattern.

NONE

1995-12-01T23:59:59.000Z

65

Medical Applications of Space Light-Emitting Diode Technology--Space Station and Beyond  

SciTech Connect (OSTI)

Space light-emitting diode (LED) technology has provided medicine with a new tool capable of delivering light deep into tissues of the body, at wavelengths which are biologically optimal for cancer treatment and wound healing. This LED technology has already flown on Space Shuttle missions, and shows promise for wound healing applications of benefit to Space Station astronauts.

Whelan, H.T.; Houle, J.M.; Donohoe, D.L.; Bajic, D.M.; Schmidt, M.H.; Reichert, K.W.; Weyenberg, G.T.; Larson, D.L.; Meyer, G.A.; Caviness, J.A.

1999-06-01T23:59:59.000Z

66

Thermoelectrically Pumped Light-Emitting Diodes Operating above Unity Efficiency  

E-Print Network [OSTI]

A heated semiconductor light-emitting diode at low forward bias voltage V

Santhanam, Parthiban

67

Light-Emitting Diodes in the Solid-State Lighting Systems  

E-Print Network [OSTI]

Red and green light-emitting diodes (LEDs) had been produced for several decades before blue emitting diodes, suitable for lighting applications, were widely available. Today, we have the possibility of combining the three fundamental colours to have a bright white light. And therefore, a new form of lighting, the solid-state lighting, has now become a reality. Here we discuss LEDs and some of their applications in displays and lamps.

Sparavigna, Amelia Carolina

2014-01-01T23:59:59.000Z

68

Matrix-addressable III-nitride light emitting diode arrays on silicon substrates by flip-chip technology.  

E-Print Network [OSTI]

??Matrix-addressable light emitting diode (LED) micro-arrays on sapphire substrates have been reported. In the fabrication process, complicated chemical-mechanical polishing after planarization with oxides, or conformal… (more)

Keung, Chi Wing

2007-01-01T23:59:59.000Z

69

Improved Cognitive Function After Transcranial, Light-Emitting Diode Treatments in Chronic, Traumatic Brain Injury: Two Case Reports  

E-Print Network [OSTI]

Objective: Two chronic, traumatic brain injury (TBI) cases, where cognition improved following treatment with red and near-infrared light-emitting diodes (LEDs), applied transcranially to forehead and scalp areas, are ...

Naeser, Margaret A.

70

Sandia National Laboratories: light-emitting diode  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmitted for USMaterialsthe Goal ofco-locatinglight-emitting diode Sandian

71

Optical manifold for light-emitting diodes  

DOE Patents [OSTI]

An optical manifold for efficiently combining a plurality of blue LED outputs to illuminate a phosphor for a single, substantially homogeneous output, in a small, cost-effective package. Embodiments are disclosed that use a single or multiple LEDs and a remote phosphor, and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. A further aperture mask is used to boost phosphor luminance with only modest loss of luminosity. Alternative non-recycling embodiments provide blue and yellow light in collimated beams, either separately or combined into white.

Chaves, Julio C.; Falicoff, Waqidi; Minano, Juan C.; Benitez, Pablo; Parkyn Jr., William A.; Alvarez, Roberto; Dross, Oliver

2008-06-03T23:59:59.000Z

72

White emitting polyfluorene functionalized with azide hybridized on near-UV light emitting diode  

E-Print Network [OSTI]

White emitting polyfluorene functionalized with azide hybridized on near-UV light emitting diode@fen.bilkent.edu.tr Abstract: We develop and demonstrate high-quality white light generation that relies on the use of a single-UV LED platform. The high-quality white emission from the polyfluorene is achieved by using the azide

Demir, Hilmi Volkan

73

Injection and transport processes in organic light emitting diodes based on N. Huby a,b  

E-Print Network [OSTI]

1 Injection and transport processes in organic light emitting diodes based on a silole. N. Huby a- conductors in light emitting diodes1 . The different fields of research around the organic electronic allowed

Boyer, Edmond

74

High-Efficiency and Stable White Organic Light-Emitting Diode...  

Broader source: Energy.gov (indexed) [DOE]

Efficiency and Stable White Organic Light-Emitting Diode Using a Single Emitter High-Efficiency and Stable White Organic Light-Emitting Diode Using a Single Emitter Presenter: Jian...

75

P-66: Personal Communication System Hand-set with Organic Light Emitting Diode Display  

E-Print Network [OSTI]

Light Emitting Diodes (OLED) display panel. As a result, OLEDs technology was applied to a display for a

Seungeun Lee; Wonseok Oh; Sungchul Lee; Jongchan Choi

76

Correlation between the Indium Tin Oxide morphology and the performances of polymer light-emitting diodes  

E-Print Network [OSTI]

: This paper reports on performance enhancement of polymer light-emitting diodes (PLEDs) based on poly(2,5-bis. Keywords : Polymer light emitting diode; Indium tin oxide; Atomic force microscopy; Rutherford backscattering spectroscopy 1. Introduction Polymer light-emitting diodes (PLEDs) have received worldwide

Paris-Sud XI, Université de

77

High efficiency light emitting diode with anisotropically etched GaN-sapphire interface  

E-Print Network [OSTI]

High efficiency light emitting diode with anisotropically etched GaN- sapphire interface M. H. Lo and optimization of a light-emitting diode projection micro-stereolithography three-dimensional manufacturingGaN micro-light emitting diodes Appl. Phys. Lett. 101, 231110 (2012) A bright cadmium-free, hybrid organic

78

Enhancement of Barrier Properties Using Ultrathin Hybrid Passivation Layer for Organic Light Emitting Diodes  

E-Print Network [OSTI]

acrylate layer and MS-31 (MgO : SiO2 ¼ 3 : 1 wt %) layer was adopted in organic light emitting diode (OLED the penetrations of oxygen and moisture. [DOI: 10.1143/JJAP.45.5970] KEYWORDS: organic light emitting diode (OLED. Introduction As a next generation display, the organic light emitting diode (OLED) has to great performances

Hwang, Sung Woo

79

Poly(p-phenylene vinylene)/tris(8-hydroxy) quinoline aluminum heterostructure light emitting diode  

E-Print Network [OSTI]

Poly(p-phenylene vinylene)/tris(8-hydroxy) quinoline aluminum heterostructure light emitting diode are presented from polymer/molecular organic heterostructure light emitting diodes composed of a layer,2 organic light emitting diodes OLEDs utilizing fluorescent molecules have attracted considerable interest

80

Light extraction analysis and enhancement in a quantum dot light emitting diode  

E-Print Network [OSTI]

Light extraction analysis and enhancement in a quantum dot light emitting diode Ruidong Zhu outcoupling and angular performance of quantum dot light emitting diode (QLED). To illustrate the design principles, we use a red QLED as an example and compare its performance with an organic light emitting diode

Wu, Shin-Tson

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Enhanced coupling of light from organic light emitting diodes using nanoporous films  

E-Print Network [OSTI]

Enhanced coupling of light from organic light emitting diodes using nanoporous films H. J. Peng, Y the light extraction efficiency for organic light emitting diode OLED . Nanoporous alumina film was used by Bragg scattering. The corrugated light- emitting diode had two-times the efficiency as compared

82

Room temperature 1.6 m electroluminescence from Ge light emitting diode on Si substrate  

E-Print Network [OSTI]

Room temperature 1.6 µm electroluminescence from Ge light emitting diode on Si substrate Szu n+/p light emitting diode on a Si substrate. Unlike normal electrically pumped devices, this device.4670) Optical materials; (230.3670) Light-emitting diodes. References and links 1. L. C. Kimerling, "Silicon

Vuckovic, Jelena

83

Point defect engineered Si sub-bandgap light-emitting diode  

E-Print Network [OSTI]

Point defect engineered Si sub-bandgap light-emitting diode Jiming Bao1 , Malek Tabbal1,2 , Taegon light emission in Si and demonstrate a sub-bandgap light emitting diode based on the introduction OCIS codes: (230.3670) Light-emitting diodes; (160.6000) Semiconductors; (130-0250) Optoelectronics

Bao, Jiming

84

Organic light-emitting diodes from homoleptic square planar complexes  

DOE Patents [OSTI]

Homoleptic square planar complexes [M(N.LAMBDA.N).sub.2], wherein two identical N.LAMBDA.N bidentate anionic ligands are coordinated to the M(II) metal center, including bidentate square planar complexes of triazolates, possess optical and electrical properties that make them useful for a wide variety of optical and electrical devices and applications. In particular, the complexes are useful for obtaining white or monochromatic organic light-emitting diodes ("OLEDs"). Improved white organic light emitting diode ("WOLED") designs have improved efficacy and/or color stability at high brightness in single- or two-emitter white or monochrome OLEDs that utilize homoleptic square planar complexes, including bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) ("Pt(ptp).sub.2").

Omary, Mohammad A

2013-11-12T23:59:59.000Z

85

THE FABRICATION AND ANALYSIS OF QUANTUM-DOT THIN FILM LIGHT EMITTING DIODES FOR USE IN DISPLAYS TECHNOLOGIES.  

E-Print Network [OSTI]

??The quantum dot has many applications, one of which is the light emitting diode. Quantum dot light emitting diodes were fabricated for their use in… (more)

Pickering, Shawn

2011-01-01T23:59:59.000Z

86

Amber light-emitting diode comprising a group III-nitride nanowire active region  

DOE Patents [OSTI]

A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

2014-07-22T23:59:59.000Z

87

Photoionization of optically trapped ultracold atoms with a high-power light-emitting diode  

SciTech Connect (OSTI)

Photoionization of laser-cooled atoms using short pulses of a high-power light-emitting diode (LED) is demonstrated. Light pulses as short as 30 ns have been realized with the simple LED driver circuit. We measure the ionization cross section of {sup 85}Rb atoms in the first excited state, and show how this technique can be used for calibrating efficiencies of ion detector assemblies.

Goetz, Simone; Hoeltkemeier, Bastian; Amthor, Thomas; Weidemueller, Matthias [Physikalisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg (Germany)

2013-04-15T23:59:59.000Z

88

Demonstration Assessment of Light-Emitting Diode (LED) Parking Lot Lighting at T.J.Maxx in Manchester, NH Phase I  

SciTech Connect (OSTI)

A report describing the process and results of replacing existing parking lot lighting, looking at a LED option with occupancy sensors, and conventional alternates. Criteria include payback, light levels, occupant satisfaction. This report is Phase I of II. Phase I deals with initial installation.

Myer, Michael; Goettel, Russell T.

2010-06-29T23:59:59.000Z

89

Synthesis and optical properties of cadmium selenide quantum dots for white light-emitting diode application  

SciTech Connect (OSTI)

Highlights: ? Stable CdSe QDs were synthesized by the one-step and two-level process respectively. ? The fabricated white LEDs show good white balance. ? CdSe QDs present well green to yellow band luminescence. ? CdSe QDs displayed a broad excitation band. - Abstract: Yellow light-emitting cadmium selenide quantum dots were synthesized using one-step and two-step methods in an aqueous medium. The structural luminescent properties of these quantum dots were investigated. The obtained cadmium selenide quantum dots displayed a broad excitation band suitable for blue or near-ultraviolet light-emitting diode applications. White light-emitting diodes were fabricated by coating the cadmium selenide samples onto a 460 nm-emitting indium gallium nitrite chip. Both samples exhibited good white balance. Under a 20 mA working current, the white light-emitting diode fabricated via the one-step and two-step methods showed Commission Internationale de l’Éclairage coordinates at (0.27, 0.23) and (0.27, 0.33), respectively, and a color rendering index equal to 41 and 37, respectively. The one-step approach was simpler, greener, and more effective than the two-step approach. The one-step approach can be enhanced by combining cadmium selenide quantum dots with proper phosphors.

Xu, Xianmei; Wang, Yilin; Gule, Teri; Luo, Qiang [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Zhou, Liya, E-mail: zhouliyatf@163.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Gong, Fuzhong [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China)

2013-03-15T23:59:59.000Z

90

COLLOIDAL ELECTROLUMINESCENCE: NOVEL ROUTES TO CONTROLLED EMISSION OF ORGANIC LIGHT EMITTING DIODE DEVICES.  

E-Print Network [OSTI]

??In recent years the importance of the organic light emitting diode (OLED) has grown immensely, and the past two decades have seen ongoing and exhaustive… (more)

Huebner, Christopher

2009-01-01T23:59:59.000Z

91

Power control architectures for cold cathode fluorescent lamp and light emitting diode based light sources.  

E-Print Network [OSTI]

?? In this dissertation, two different energy efficient power supply topologies are introduced for controlling cold cathode fluorescent lamp (CCFL) and high-brightness light emitting diode… (more)

Doshi, Montu V.

2010-01-01T23:59:59.000Z

92

Nanocrystalline Silicon Quantum Dot Light Emitting Diodes Using Metal Oxide Charge Transport Layers.  

E-Print Network [OSTI]

??Silicon-based lighting show promise for display and solid state lighting use. Here we demonstrate a novel thin film light emitting diode device using nanocrystalline silicon… (more)

Zhu, Jiayuan

2013-01-01T23:59:59.000Z

93

Low-Cost Light-Emitting Diode Luminaire for General Illumination...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Santa Barbara Technology Center This project is demonstrating an efficient and stable white organic light-emitting diode (WOLED) using a single emitter on a planar glass...

94

Luminescence and Squeezing of a Superconducting Light Emitting Diode  

E-Print Network [OSTI]

We investigate a semiconductor $p$-$n$ junction in contact with superconducting leads that is operated under forward bias as a light-emitting diode. The presence of superconductivity results in a significant increase of the electroluminescence in a certain frequency window. We demonstrate that the tunneling of Cooper pairs induces an additional luminescence peak on resonance. There is a transfer of superconducting to photonic coherence which results in the emission of entangled photon pairs and squeezing of the fluctuations in the quadrature amplitudes of the emitted light. The squeezing angle can be electrically manipulated by changing the relative phase of the order parameters in the superconductors. We finally derive the conditions for lasing in the system and show that the laser threshold is reduced due to superconductivity. This shows how macroscopic coherence of a superconductor can be used to control the properties of light.

Patrik Hlobil; Peter P. Orth

2015-02-17T23:59:59.000Z

95

Luminescence and Squeezing of a Superconducting Light Emitting Diode  

E-Print Network [OSTI]

We investigate a semiconductor $p$-$n$ junction in contact with superconducting leads that is operated under forward bias as a light-emitting diode. The presence of superconductivity results in a significant increase of the electroluminescence in a certain frequency window. We demonstrate that the tunneling of Cooper pairs induces an additional luminescence peak on resonance. There is a transfer of superconducting to photonic coherence which results in the emission of entangled photon pairs and squeezing of the fluctuations in the quadrature amplitudes of the emitted light. The squeezing angle can be electrically manipulated by changing the relative phase of the order parameters in the superconductors. We finally derive the conditions for lasing in the system and show that the laser threshold is reduced due to superconductivity. This shows how macroscopic coherence of a superconductor can be used to control the properties of light.

Hlobil, Patrik

2015-01-01T23:59:59.000Z

96

Semiconductor Nanocrystals-Based White Light Emitting Diodes  

SciTech Connect (OSTI)

In response to the demands for energy and the concerns of global warming and climate change, energy efficient and environmentally friendly solid state lighting, such as white light emitting diodes (WLEDs), is considered to be the most promising and suitable light source. Because of their small size, high efficiency, and long lifetime, WLEDs based on colloidal semiconductor nanocrystals (or quantum dots) are emerging as a completely new technology platform for the development of flat-panel displays and solid state lighting, exhibiting the potential to replace the conventionally used incandescent and fluorescent lamps. This replacement could cut the ever-increasing energy consumption, solve the problem of rapidly depleting fossil fuel reserves, and improve the quality of the global environment. In this review, we highlight the recent progress in semiconductor nanocrystals-based WLEDs, compare different approaches for generating white light, and discuss the benefits and challenges of the solid state lighting technology.

Dai, Quanqin [ORNL; Hu, Michael Z. [ORNL; Duty, Chad E [ORNL

2010-01-01T23:59:59.000Z

97

White organic light-emitting diodes: Status and perspective  

E-Print Network [OSTI]

White organic light-emitting diodes (OLEDs) are ultra-thin, large-area light sources made from organic semiconductor materials. Over the last decades, much research has been spent on finding the suitable materials to realize highly efficient monochrome and white OLEDs. With their high efficiency, color-tunability, and color-quality, white OLEDs are emerging to become one of the next generation light sources. In this review, we discuss the physics of a variety of device concepts that are introduced to realize white OLEDs based on both polymer and small molecule organic materi als. Owing to the fact that about 80 % of the internally generated photons are trapped within the thin-film layer structure, we put a second focus on reviewing promising concepts for improved light outcoupling.

Reineke, Sebastian; Lüssem, Björn; Leo, Karl

2013-01-01T23:59:59.000Z

98

Model for Triplet State Engineering in Organic Light Emitting Diodes  

E-Print Network [OSTI]

Engineering the position of the lowest triplet state (T1) relative to the first excited singlet state (S1) is of great importance in improving the efficiencies of organic light emitting diodes and organic photovoltaic cells. We have carried out model exact calculations of substituted polyene chains to understand the factors that affect the energy gap between S1 and T1. The factors studied are backbone dimerisation, different donor-acceptor substitutions and twisted geometry. The largest system studied is an eighteen carbon polyene which spans a Hilbert space of about 991 million. We show that for reverse intersystem crossing (RISC) process, the best system involves substituting all carbon sites on one half of the polyene with donors and the other half with acceptors.

Prodhan, Suryoday; Ramasesha, S

2014-01-01T23:59:59.000Z

99

Electroluminescence property of organic light emitting diode (OLED)  

SciTech Connect (OSTI)

Transport properties of electrons and holes were investigated not only in a anthracene-containing poly(p-phenylene-ethynylene)- alt - poly(p-phenylene-vinylene) (PPE-PPV) polymer (AnE-PVstat) light emitting diodes (OLED) but also in an ITO/Ag/polymer/Ag electron and ITO/PEDOT:PSS/polymer/Au hole only devices. Mobility of injected carriers followed the Poole-Frenkel type conduction mechanism and distinguished in the frequency range due to the difference of transit times in admittance measurement. Beginning of light output took place at the turn-on voltage (or flat band voltage), 1.8 V, which was the difference of energy band gap of polymer and two barrier offsets between metals and polymer.

Özdemir, Orhan; Kavak, Pelin; Saatci, A. Evrim; Gökdemir, F. P?nar; Menda, U. Deneb; Can, Nursel; Kutlu, Kubilay [Y?ld?z Technical University, Department of Physics, Esenler, Istanbul (Turkey); Tekin, Emine; Pravadal?, Selin [National Metrology Inst?tute of Turkey (TUB?TAK-UME), Kocaeli (Turkey)

2013-12-16T23:59:59.000Z

100

Light emitting diode package element with internal meniscus for bubble free lens placement  

DOE Patents [OSTI]

A method for fabricating a light emitting diode (LED) package comprising providing an LED chip and covering at least part of the LED chip with a liquid encapsulant having a radius of curvature. An optical element is provided having a bottom surface with at least a portion having a radius of curvature larger than the liquid encapsulant. The larger radius of curvature portion of the optical element is brought into contact with the liquid encapsulant. The optical element is then moved closer to the LED chip, growing the contact area between said optical element and said liquid encapsulant. The liquid encapsulant is then cured. A light emitting diode comprising a substrate with an LED chip mounted to it. A meniscus ring is on the substrate around the LED chip with the meniscus ring having a meniscus holding feature. An inner encapsulant is provided over the LED chip with the inner encapsulant having a contacting surface on the substrate, with the meniscus holding feature which defines the edge of the contacting surface. An optical element is included having a bottom surface with at least a portion that is concave. The optical element is arranged on the substrate with the concave portion over the LED chip. A contacting encapsulant is included between the inner encapsulant and optical element.

Tarsa, Eric; Yuan, Thomas C.; Becerra, Maryanne; Yadev, Praveen

2010-09-28T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Internal efficiency of InGaN light-emitting diodes: Beyond a quasiequilibrium model  

SciTech Connect (OSTI)

We propose a model to better investigate InGaN light-emitting diode (LED) internal efficiency by extending beyond the usual total carrier density rate equation approach. To illustrate its capability, the model is applied to study intrinsic performance differences between violet and green LEDs. The simulations show performance differences, at different current densities and temperatures, arising from variations in spontaneous emission and heat loss rates. By tracking the momentum-resolved carrier populations, these rate changes are, in turn, traced to differences in bandstructure and plasma heating. The latter leads to carrier distributions that deviate from the quasiequilibrium ones at lattice temperature.

Chow, Weng W.; Crawford, Mary H.; Tsao, Jeffrey Y.; Kneissl, Michael

2010-01-01T23:59:59.000Z

102

Light extraction from organic light-emitting diodes for lighting applications by sand-blasting  

E-Print Network [OSTI]

Light extraction from organic light-emitting diodes for lighting applications by sand@ust.hk Abstract: Light extraction from organic light-emitting diodes (OLEDs) by scattering the light is one of the effective methods for large-area lighting applications. In this paper, we present a very simple and cost

103

Red-emitting fluorescent Organic Light emitting Diodes with low sensitivity to self-quenching  

E-Print Network [OSTI]

Red-emitting fluorescent Organic Light emitting Diodes with low sensitivity to self-quenching S, France *E-mail : sebastien.forget@univ-paris13.fr Keywords: OLED, quenching, doping, red-emitting organic. We herein report on Organic Light-Emitting Diodes (OLEDs) based on a fluorescent amorphous red

Paris-Sud XI, Université de

104

White Organic Light-Emitting Diodes with fine chromaticity tuning via ultrathin layer position shifting  

E-Print Network [OSTI]

White Organic Light-Emitting Diodes with fine chromaticity tuning via ultrathin layer position : Non-doped white organic light-emitting diodes using an ultrathin yellow-emitting layer of rubrene (5 via a bright white (WOLED) with CIE coordinates (x= 0.33, y= 0.32), a ext of 1.9%, and a color

Paris-Sud XI, Université de

105

Thermal And Mechanical Analysis of High-power Light-emitting Diodes with Ceramic Packages  

E-Print Network [OSTI]

In this paper we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermo-mechanical simulation were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistance from the junction to the ambient was decreased from 76.1 oC/W to 45.3 oC/W by replacing plastic mould to ceramic mould for LED packages. Higher level of thermo-mechanical stresses in the chip were found for LEDs with ceramic packages despite of less mismatching coefficients of thermal expansion comparing with plastic packages. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high power LEDs with ceramic packages is critically important and should be in charge of delaminating interface layers in the packages.

J. Hu; L. Yang; M. -W. Shin

2008-01-07T23:59:59.000Z

106

Tunnel junction multiple wavelength light-emitting diodes  

DOE Patents [OSTI]

A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect. 5 figs.

Olson, J.M.; Kurtz, S.R.

1992-11-24T23:59:59.000Z

107

Tunnel junction multiple wavelength light-emitting diodes  

DOE Patents [OSTI]

A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO)

1992-01-01T23:59:59.000Z

108

Interface electronic structures of organic light-emitting diodes with WO3 interlayer: A study by photoelectron spectroscopy  

E-Print Network [OSTI]

Interface electronic structures of organic light-emitting diodes with WO3 interlayer: A study injec- tion and transport layers in an organic light-emitting diode (OLED) structure has been studied B.V. All rights reserved. 1. Introduction OLEDs (organic light-emitting diodes) are display de

Kim, Sehun

109

4.2: Design of an Improved Pixel for a Polysilicon Active Matrix Organic Light Emitting Diode Display  

E-Print Network [OSTI]

4.2: Design of an Improved Pixel for a Polysilicon Active Matrix Organic Light Emitting Diode active matrix organic light emitting diode (AMOLED) pixel with high pixel to pixel luminance uniformity such as organic light emitting diodes (OLEDs) are presently of great interest due to their potential application

110

Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of light emitting diodes  

E-Print Network [OSTI]

of light emitting diodes Ronald A. Arif, Yik-Khoon Ee, and Nelson Tansu Citation: Appl. Phys. Lett. 91 extraction in GaN-based light emitting diodes Appl. Phys. Lett. 100, 061107 (2012) Electrically driven nanopyramid green light emitting diode Appl. Phys. Lett. 100, 061106 (2012) Ultraviolet electroluminescence

Gilchrist, James F.

111

High-density organic light emitting diodes by nanoimprint technology Krutarth Trivedi, Caleb Nelson, Li Tao, Mathew Goeckner, Walter Hua)  

E-Print Network [OSTI]

High-density organic light emitting diodes by nanoimprint technology Krutarth Trivedi, Caleb Nelson sources. Despite the considerable development of inorganic semiconductor based light emitting diodes of miniaturization to nanoscale. Organic light emitting diode (OLED) technology is immune to quantum confinement

Hu, Wenchuang "Walter"

112

Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes  

E-Print Network [OSTI]

Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes S. L. Rumyantseva well light emitting diodes. The light intensity noise was measured as a function of wavelength within the light emitting diode spectral emission line. The spectral noise density is found to increase

Wetzel, Christian M.

113

Amorphous silicon as electron transport layer for colloidal semiconductor nanocrystals light emitting diode  

SciTech Connect (OSTI)

We demonstrate the fabrication of light-emitting diodes (LEDs) made from all-inorganic colloidal semiconducting nanocrystals (NCs). The diode utilizes a sandwich structure formed by placing CdSe/CdS NCs between two layers of Si and Ag{sub x}O, which act as electron- and hole-transporting materials, respectively. The photoluminescence properties of NCs are rendered less dependent upon surface chemistry and chemical environment by growing a thick CdS shell. It also enhances stability of the NCs during the process of magnetron sputtering for silicon deposition. The resulting LED device exhibits a low turn-on voltage of 2.5 V and the maximum external quantum efficiency of nearly 0.08%.

Song Tao; Shen Xiaojuan; Sun Baoquan [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, 199 Ren'ai Road, Suzhou 215123 (China); Zhang Fute [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, 199 Ren'ai Road, Suzhou 215123 (China); Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Soochow University, Suzhou 215123 (China); Zhang Xiaohong [Nano-Organic Photoelectronic Laboratory and Laboratory of Organic Optoelectronic Functional Materials and Molecular Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhu Xiulin [Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering, Soochow University, Suzhou 215123 (China)

2009-12-07T23:59:59.000Z

114

Light-emitting diode spherical packages: an equation for the light transmission efficiency  

E-Print Network [OSTI]

Virtually all light-emitting diodes (LEDs) are encapsulated with a transparent epoxy or silicone-gel. In this paper we analyze the optical efficiency of spherical encapsulants. We develop a quasi-radiometric equation for the light transmission efficiency, which incorporates some ideas of Monte-Carlo ray tracing into the context of radiometry. The approach includes the extended source nature of the LED chip, and the chip radiance distribution. The equation is an explicit function of the size and the refractive index of the package, and also of several chip parameters such as shape, size, radiance, and location inside the package. To illustrate the use of this equation, we analyze several packaging configurations of practical interest; for example, a hemispherical dome with multiple chips, a flat encapsulation as a special case of the spherical package, and approximate calculations of an encapsulant with a photonic crystal LED or with a photonic quasi crystal LED. These calculations are compared with Monte-Carl...

Moreno, Ivan; Avendano-Alejo, Maximino; 10.1364/AO.49.000012

2011-01-01T23:59:59.000Z

115

Sidewall passivation for InGaN/GaN nanopillar light emitting diodes  

SciTech Connect (OSTI)

We studied the effect of sidewall passivation on InGaN/GaN multiquantum well-based nanopillar light emitting diode (LED) performance. In this research, the effects of varying etch rate, KOH treatment, and sulfur passivation were studied for reducing nanopillar sidewall damage and improving device efficiency. Nanopillars prepared under optimal etching conditions showed higher photoluminescence intensity compared with starting planar epilayers. Furthermore, nanopillar LEDs with and without sulfur passivation were compared through electrical and optical characterization. Suppressed leakage current under reverse bias and four times higher electroluminescence (EL) intensity were observed for passivated nanopillar LEDs compared with unpassivated nanopillar LEDs. The suppressed leakage current and EL intensity enhancement reflect the reduction of non-radiative recombination at the nanopillar sidewalls. In addition, the effect of sulfur passivation was found to be very stable, and further insight into its mechanism was gained through transmission electron microscopy.

Choi, Won Hyuck; Abraham, Michael; Yu, Shih-Ying [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); You, Guanjun; Liu, Jie; Wang, Li; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mohney, Suzanne E., E-mail: mohney@ems.psu.edu [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2014-07-07T23:59:59.000Z

116

Components, production processes, and recommendations for future research in organic light emitting diodes  

E-Print Network [OSTI]

Organic Light Emitting Diodes (OLEDs) are small, optoelectronic devices that can be used in the production of energy-efficient, high definition displays in cell phones, computers, and televisions. These devices have great ...

Hunting, Lindsay (Lindsay E.)

2009-01-01T23:59:59.000Z

117

Storage of charge carriers on emitter molecules in organic light-emitting diodes  

E-Print Network [OSTI]

Organic light-emitting diodes (OLEDs) using the red phosphorescent emitter iridium(III)bis(2-methyldibenzo[f,h]quinoxaline) (acetylacetonate) [Ir(MDQ)[subscript 2](acac)] are studied by time-resolved electroluminescence ...

Reineke, Sebastian

118

A spin light emitting diode incorporating ability of electrical helicity switching  

SciTech Connect (OSTI)

Fabrication and optical characteristics of a spin light-emitting-diode (spin-LED) having dual spin-injection electrodes with anti-parallel magnetization configuration are reported. Alternating a current between the two electrodes using a computer-driven current source has led us to the observation of helicity switching of circular polarization at the frequency of 1 kHz. Neither external magnetic fields nor optical delay modulators were used. Sending dc-currents to both electrodes with appropriate ratio has resulted in continuous variation of circular polarization between the two opposite helicity, including the null polarization. These results suggest that the tested spin-LED has the feasibility of a monolithic light source whose circular polarization can be switched or continuously tuned all electrically.

Nishizawa, N., E-mail: nishizawa@isl.titech.ac.jp; Nishibayashi, K.; Munekata, H. [Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259-J3-15 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

2014-03-17T23:59:59.000Z

119

Note: A portable, light-emitting diode-based ruby fluorescence spectrometer for high-pressure calibration  

SciTech Connect (OSTI)

Ruby (Al{sub 2}O{sub 3}, with {approx}0.5 wt. % Cr doping) is one of the most widely used manometers at the giga-Pascal scale. Traditionally, its fluorescence is excited with intense laser sources. Here, I present a simple, robust, and portable design that employs light-emitting diodes (LEDs) instead. This LED-based system is safer in comparison with laser-based ones.

Feng Yejun [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2011-04-15T23:59:59.000Z

120

Vacuum-free lamination of low work function cathode for efficient solution-processed organic light-emitting diodes  

E-Print Network [OSTI]

-coated organic light-emitting diode is transferred from a soft polydimethylsiloxane (PDMS) mold by lamination, or blade coating [1,2] for organic light emitting diode (OLED) as well as solar cell. The top electrodeVacuum-free lamination of low work function cathode for efficient solution-processed organic light-emitting

Meng, Hsin-Fei

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Surface Plasmon Enhanced Phosphorescent Organic Light Emitting Diodes  

SciTech Connect (OSTI)

The objective of the proposed work was to develop the fundamental understanding and practical techniques for enhancement of Phosphorescent Organic Light Emitting Diodes (PhOLEDs) performance by utilizing radiative decay control technology. Briefly, the main technical goal is the acceleration of radiative recombination rate in organometallic triplet emitters by using the interaction with surface plasmon resonances in noble metal nanostructures. Increased photonic output will enable one to eliminate constraints imposed on PhOLED efficiency by triplet-triplet annihilation, triplet-polaron annihilation, and saturation of chromophores with long radiative decay times. Surface plasmon enhanced (SPE) PhOLEDs will operate more efficiently at high injection current densities and will be less prone to degradation mechanisms. Additionally, introduction of metal nanostructures into PhOLEDs may improve their performance due to the improvement of the charge transport through organic layers via multiple possible mechanisms ('electrical bridging' effects, doping-like phenomena, etc.). SPE PhOLED technology is particularly beneficial for solution-fabricated electrophosphorescent devices. Small transition moment of triplet emitters allows achieving a significant enhancement of the emission rate while keeping undesirable quenching processes introduced by the metal nanostructures at a reasonably low level. Plasmonic structures can be introduced easily into solution-fabricated PhOLEDs by blending and spin coating techniques and can be used for enhancement of performance in existing device architectures. This constitutes a significant benefit for a large scale fabrication of PhOLEDs, e.g. by roll-to-roll fabrication techniques. Besides multieexciton annihilation, the power efficacy of PhOLEDs is often limited by high operational bias voltages required for overcoming built-in potential barriers to injection and transport of electrical charges through a device. This problem is especially pronounced in solution processed OLEDs lacking the accuracy and precision of fabrication found in their small molecule counterparts. From this point of view, it seems beneficial to develop materials allowing reduction of the operation bias voltage via improvement of the charge injection. The materials sought have to be compatible with solution-based fabrication process and allow easy incorporation of metal nanostructures.

Guillermo Bazan; Alexander Mikhailovsky

2008-08-01T23:59:59.000Z

122

Method and apparatus for improving the performance of light emitting diodes  

DOE Patents [OSTI]

A method for increasing the resistance of a light emitting diode and other semiconductor devices to extremes of temperature is disclosed. During the manufacture of the light emitting diode, a liquid coating is applied to the light emitting die after the die has been placed in its lead frame. After the liquid coating has been placed on the die and its lead frames, a thermosetting encapsulant material is placed over the coating. The operation that cures the thermosetting material leaves the coating liquid intact. As the die and the encapsulant expand and contract at different rates with respect to changes in temperature, and as in known light emitting diodes the encapsulating material adheres to the die and lead frames, this liquid coating reduces the stresses that these different rates of expansion and contraction normally cause by eliminating the adherence of the encapsulating material to the die and frame.

Lowery, Christopher H. (Fremont, CA); McElfresh, David K. (Union City, CA); Burchet, Steve (Cedar Crest, NM); Adolf, Douglas B. (Albuquerque, NM); Martin, James (Tijeras, NM)

1996-01-01T23:59:59.000Z

123

Fabrication and Characterization of New Hybrid Organic Light Emitting Diode (OLED): Europium-picrate-triethylene oxide Complex  

SciTech Connect (OSTI)

Thin-film light emitting devices based on organic materials have attracted vast interest in applications such as light emitting diode (LED) and flat-panel display. The organic material can be attached with inorganic material to enhance the performance of the light emitting device. A hybrid OLED based on a new complex of europium picrate (Eu-pic) with triethylene oxide (EO3) ligand is fabricated. The OLED is fabricated by using spin coating technique with acetone as the solvent and aluminum as the top electrode. The optical, photoluminescence (PL) and electrical properties of the sample are carried out by UV-Vis spectroscopy (Jasco V-750), luminescence spectroscopy (Perkin Elmer LS-500) and source measure unit (SMU)(Keithly), respectively.

Sarjidan, M. A. Mohd; Abu Zakaria, N. Z. A.; Abd. Majid, W. H. [Solid State Research Laboratory, Department of Physics, University of Malaya, 50603, Kuala Lumpur (Malaysia); Kusrini, Eny; Saleh, M. I. [School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia)

2009-07-07T23:59:59.000Z

124

Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes  

SciTech Connect (OSTI)

This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

Dr. Anatoly Shteynberg, PhD

2006-08-17T23:59:59.000Z

125

Intramolecular excimer emission as a blue light source in fluorescent organic light emitting diodes: a promising molecular design  

E-Print Network [OSTI]

Intramolecular excimer emission as a blue light source in fluorescent organic light emitting diodes Light Emitting Diode (OLED), intermolecular p­p interactions should be usually suppressed to avoid any Emitting Diodes (SMOLEDs) is almost absent from the literature. In this work, three aryl-substituted Di

Boyer, Edmond

126

Demonstration Assessment of Light-Emitting Diode Roadway Lighting on the FDR Drive in New York, New York  

SciTech Connect (OSTI)

This a report about a field study of light-emitting diodes street lights by four different manufacturers installed on the FDR Drive in New York City, NY.

Myer, Michael; Hazra, Oindrila; Kinzey, Bruce R.

2011-12-01T23:59:59.000Z

127

Printed assemblies of ultrathin, microscale inorganic light emitting diodes for deformable and semitransparent displays  

DOE Patents [OSTI]

Described herein are printable structures and methods for making, assembling and arranging electronic devices. A number of the methods described herein are useful for assembling electronic devices where one or more device components are embedded in a polymer which is patterned during the embedding process with trenches for electrical interconnects between device components. Some methods described herein are useful for assembling electronic devices by printing methods, such as by dry transfer contact printing methods. Also described herein are GaN light emitting diodes and methods for making and arranging GaN light emitting diodes, for example for display or lighting systems.

Rogers, John A; Nuzzo, Ralph; Kim, Hoon-sik; Brueckner, Eric; Park, Sang Il; Kim, Rak Hwan

2014-10-21T23:59:59.000Z

128

New red phosphor for near-ultraviolet light-emitting diodes with high color-purity  

SciTech Connect (OSTI)

New red phosphors, Na{sub 5}Eu(MoO{sub 4}){sub 4} doped with boron oxide were prepared by the solid-state reaction. Their structure and photo-luminescent properties were investigated. With the introduction of boron oxide, the red emission intensity of the phosphors under 395 nm excitation is strengthened, with high color-purity (x = 0.673, y = 0.327). The single red light-emitting diode was obtained by combining InGaN chip with the red phosphor, bright red light can be observed by naked eyes from the red light-emitting diodes under a forward bias of 20 mA.

Wang, Zhengliang, E-mail: wzhl_ww@yahoo.com.cn [School of Chemistry and Biotechnology, Yunnan Nationalities University, Kunming, Yunnan 650031 (China)] [School of Chemistry and Biotechnology, Yunnan Nationalities University, Kunming, Yunnan 650031 (China); He, Pei; Wang, Rui [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China)] [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China); Zhao, Jishou [School of Chemistry and Biotechnology, Yunnan Nationalities University, Kunming, Yunnan 650031 (China)] [School of Chemistry and Biotechnology, Yunnan Nationalities University, Kunming, Yunnan 650031 (China); Gong, Menglian [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China)] [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China)

2010-02-15T23:59:59.000Z

129

Amber-green light-emitting diodes using order-disorder Al[subscript x]In[subscript 1?x]P heterostructures  

E-Print Network [OSTI]

We demonstrate amber-green emission from Al[subscript x]In[subscript 1– x]P light-emitting diodes (LEDs) with luminescence peaked at 566?nm and 600?nm. The LEDs are metamorphically grown on GaAs substrates via a graded ...

Christian, Theresa M.

130

Understanding Drooping Light Emitting Diodes CEEM | U.S. DOE...  

Office of Science (SC) Website

Impact Understanding "droop" may result in cheaper, more efficient LEDs; LEDs are more energy efficient, smaller, and longer-lived than incandescent lamps or fluorescent...

131

Electro-luminescent cooling: light emitting diodes above unity efficiency  

E-Print Network [OSTI]

Experimental demonstration of net electro-luminescent cooling in a diode, or equivalently electroluminescence with wall-plug efficiency greater than unity, had eluded direct observation for more than five decades. We review ...

Santhanam, Parthiban

132

Electrical spin injection using GaCrN in a GaN based spin light emitting diode  

SciTech Connect (OSTI)

We have demonstrated electrical spin-injection from GaCrN dilute magnetic semiconductor (DMS) in a GaN-based spin light emitting diode (spin-LED). The remanent in-plane magnetization of the thin-film semiconducting ferromagnet has been used for introducing the spin polarized electrons into the non-magnetic InGaN quantum well. The output circular polarization obtained from the spin-LED closely follows the normalized in-plane magnetization curve of the DMS. A saturation circular polarization of ?2.5% is obtained at 200?K.

Banerjee, D.; Ganguly, S.; Saha, D., E-mail: dipankarsaha@iitb.ac.in [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai 400076 (India); Adari, R.; Sankaranarayan, S.; Kumar, A. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)] [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Aldhaheri, R. W.; Hussain, M. A.; Balamesh, A. S. [Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)] [Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2013-12-09T23:59:59.000Z

133

Local tuning of organic light-emitting diode color by dye droplet application  

E-Print Network [OSTI]

Local tuning of organic light-emitting diode color by dye droplet application T. R. Hebner and J. C 1998 We have demonstrated that fluorescent dyes may be introduced into previously fabricated polymer thin films by local application of a dye-containing droplet. The UV fluorescence spectra of the films

134

Solvent-enhanced dye diffusion in polymer thin films for polymer light-emitting diode application  

E-Print Network [OSTI]

Solvent-enhanced dye diffusion in polymer thin films for polymer light-emitting diode application 2004; accepted 24 August 2004) The method of solvent-enhanced dye diffusion for patterning full dry transfer of dye onto a device polymer film, the dye remains on the surface of the polymer layer

135

Dislocation-related trap levels in nitride-based light emitting diodes  

SciTech Connect (OSTI)

Deep level transient spectroscopy was performed on InGaN/GaN multiple quantum well light emitting diodes (LEDs) in order to determine the effect of the dislocation density on the deep intragap electronic levels. The LEDs were grown by metalorganic vapor phase epitaxy on GaN templates with a high dislocation density of 8 × 10{sup 9} cm{sup ?2} and a low dislocation density of 3 × 10{sup 8} cm{sup ?2}. Three trapping levels for electrons were revealed, named A, A1, and B, with energies E{sub A}???0.04?eV, E{sub A1}???0.13?eV, and E{sub B}???0.54?eV, respectively. The trapping level A has a much higher concentration in the LEDs grown on the template with a high density of dislocations. The logarithmic dependence of the peak amplitude on the bias pulse width for traps A and A1 identifies the defects responsible for these traps as associated with linearly arranged defects. We conclude that traps A and A1 are dislocation-related intragap energy levels.

Venturi, Giulia; Castaldini, Antonio; Cavallini, Anna [Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, Bologna 40127 (Italy); Meneghini, Matteo; Zanoni, Enrico [Department of Information Engineering, University of Padova, via Gradenigo 6/B, Padova 35131 (Italy); Zhu, Dandan; Humphreys, Colin [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2014-05-26T23:59:59.000Z

136

Stress-induced piezoelectric field in GaN-based 450-nm light-emitting diodes  

SciTech Connect (OSTI)

We investigated the influence of the built-in piezoelectric field induced by compressive stress on the characteristics of GaN-based 450-nm light-emitting diodes (LEDs) prepared on sapphire substrates of different thicknesses. As the sapphire substrate thickness was reduced, the compressive stress in the GaN layer was released, resulting in wafer bowing. The wafer bowing-induced mechanical stress altered the piezoelectric field, which in turn reduced the quantum confined Stark effect in the InGaN/GaN active region of the LED. The flat-band voltage was estimated by measuring the applied bias voltage that induced a 180° phase shift in the electro-reflectance (ER) spectrum. The piezoelectric field estimated by the ER spectra changed by ?110?kV/cm. The electroluminescence spectral peak wavelength was blue-shifted, and the internal quantum efficiency was improved by about 22% at a high injection current of 100?mA. The LED on the 60-?m-thick sapphire substrate exhibited the highest light output power of ?59?mW at an injection current of 100?mA, with the operating voltage unchanged.

Tawfik, Wael Z. [Department of Materials Science and Engineering, Chonnam National University, Yongbong 300 Gwangju 500-757 (Korea, Republic of); Department of Physics, Faculty of Science, Beni-Suef University, Beni-Suef 62511 (Egypt); Hyeon, Gil Yong; Lee, June Key, E-mail: junekey@chonnam.ac.kr [Department of Materials Science and Engineering, Chonnam National University, Yongbong 300 Gwangju 500-757 (Korea, Republic of)

2014-10-28T23:59:59.000Z

137

Effect of mechanical vibrations on light emitting diode luminaires.  

E-Print Network [OSTI]

??In this work, a LED and two types of Compact fluorescent lamps were investigated for the intensity variation due to mechanical vibrations in the range… (more)

Paladugu, Jayalakshmi

2009-01-01T23:59:59.000Z

138

Commercialization of Quantum Dot White Light Emitting Diode technology  

E-Print Network [OSTI]

It is well known that the use of high-brightness LEDs for illumination has the potential to substitute conventional lighting and revolutionize the lighting industry over the next 10 to 20 years. However, successful penetration ...

Zhao, Xinyue, M. Eng. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

139

Semiconductor-Nanocrystals-Based White Light-Emitting Diodes  

SciTech Connect (OSTI)

In response to the demands for energy and the concerns of global warming and climate change, energy efficient and environmentally friendly solid-state lighting, such as white lightemitting diodes (WLEDs), is considered to be the most promising and suitable light source. Because of their small size, high efficiency, and long lifetime, WLEDs based on colloidal semiconductor nanocrystals (or quantum dots) are emerging as a completely new technology platform for the development of flat-panel displays and solid-state lighting, exhibiting the potential to replace the conventionally used incandescent and fluorescent lamps. This replacement can cut the ever-increasing level of energy consumption, solve the problem of rapidly depleting fossil fuel reserves, and improve the quality of the global environment. In this review, the recent progress in semiconductor-nanocrystals-based WLEDs is highlighted, the different approaches for generating white light are compared, and the benefits and challenges of the solid-state lighting technology are discussed.

Dai, Quanqin [ORNL; Duty, Chad E [ORNL; Hu, Michael Z. [ORNL

2010-01-01T23:59:59.000Z

140

Evaluation of potential applications for templated arrays of heterostructural semiconductor nanowires as light emitting devices  

E-Print Network [OSTI]

While light emitting devices, such as laser diodes (LDs) and light emitting diodes (LEDs), were first introduced decades ago, they have been the subject of continuing research and improvements due to their relatively poor ...

Zou, Ting, M. Eng. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

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141

Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices  

SciTech Connect (OSTI)

Over the course of this program, Applied Materials, Inc., with generous support from the United States Department of Energy, developed a world-class three chamber III-Nitride epi cluster tool for low-cost, high volume GaN growth for the solid state lighting industry. One of the major achievements of the program was to design, build, and demonstrate the world’s largest wafer capacity HVPE chamber suitable for repeatable high volume III-Nitride template and device manufacturing. Applied Materials’ experience in developing deposition chambers for the silicon chip industry over many decades resulted in many orders of magnitude reductions in the price of transistors. That experience and understanding was used in developing this GaN epi deposition tool. The multi-chamber approach, which continues to be unique in the ability of the each chamber to deposit a section of the full device structure, unlike other cluster tools, allows for extreme flexibility in the manufacturing process. This robust architecture is suitable for not just the LED industry, but GaN power devices as well, both horizontal and vertical designs. The new HVPE technology developed allows GaN to be grown at a rate unheard of with MOCVD, up to 20x the typical MOCVD rates of 3{micro}m per hour, with bulk crystal quality better than the highest-quality commercial GaN films grown by MOCVD at a much cheaper overall cost. This is a unique development as the HVPE process has been known for decades, but never successfully commercially developed for high volume manufacturing. This research shows the potential of the first commercial-grade HVPE chamber, an elusive goal for III-V researchers and those wanting to capitalize on the promise of HVPE. Additionally, in the course of this program, Applied Materials built two MOCVD chambers, in addition to the HVPE chamber, and a robot that moves wafers between them. The MOCVD chambers demonstrated industry-leading wavelength yield for GaN based LED wafers and industry-leading uptime enabled in part by a novel in-situ cleaning process developed in this program.

Patibandla, Nag; Agrawal, Vivek

2012-12-01T23:59:59.000Z

142

Nanostructured High Performance Ultraviolet and Blue Light Emitting Diodes for Solid State Lighting  

SciTech Connect (OSTI)

We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the second 12 month contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

Arto V. Nurmikko; Jung Han

2005-09-30T23:59:59.000Z

143

NANOSTRUCTURED HIGH PERFORMANCE ULTRAVIOLET AND BLUE LIGHT EMITTING DIODES FOR SOLID STATE LIGHTING  

SciTech Connect (OSTI)

We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the first 12 month contract period include (1) new means of synthesizing zero- and one-dimensional GaN nanostructures, (2) establishment of the building blocks for making GaN-based microcavity devices, and (3) demonstration of top-down approach to nano-scale photonic devices for enhanced spontaneous emission and light extraction. These include a demonstration of eight-fold enhancement of the external emission efficiency in new InGaN QW photonic crystal structures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

Arto V. Nurmikko; Jung Han

2004-10-01T23:59:59.000Z

144

Growths of staggered InGaN quantum wells light-emitting diodes emitting at 520525 nm employing graded growth-temperature profile  

E-Print Network [OSTI]

Growths of staggered InGaN quantum wells light-emitting diodes emitting at 520­525 nm employing current spreading and light extraction in GaN-based light emitting diodes Appl. Phys. Lett. 100, 061107 (2012) Electrically driven nanopyramid green light emitting diode Appl. Phys. Lett. 100, 061106 (2012

Gilchrist, James F.

145

InP-Based Oxide-Confined 16 p.m Microcavity Light Emitting Diodes Weidong Zhou, Omar Qasaimeh, and Pallab Bhattacharya  

E-Print Network [OSTI]

InP-Based Oxide-Confined 16 p.m Microcavity Light Emitting Diodes Weidong Zhou, Omar Qasaimeh light emitting diodes (MCLEDs) have been designed, fabricated and characterized. Oxide- confined MCLEDs region emission peak and cavity resonance peak. Key words: Microcavity light emitting diode (MCLED), wet

Zhou, Weidong

146

Broadband visible light source based on AllnGaN light emitting diodes  

DOE Patents [OSTI]

A visible light source device is described based on a light emitting diode and a nanocluster-based film. The light emitting diode utilizes a semiconductor quantum well structure between n-type and p-type semiconductor materials on the top surface a substrate such as sapphire. The nanocluster-based film is deposited on the bottom surface of the substrate and can be derived from a solution of MoS.sub.2, MoSe.sub.2, WS.sub.2, and WSe.sub.2 particles of size greater than approximately 2 nm in diameter and less than approximately 15 nm in diameter, having an absorption wavelength greater than approximately 300 nm and less than approximately 650 nm.

Crawford, Mary H.; Nelson, Jeffrey S.

2003-12-16T23:59:59.000Z

147

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming  

DOE Patents [OSTI]

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

Li, Ting (Ventura, CA)

2011-04-26T23:59:59.000Z

148

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming  

DOE Patents [OSTI]

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

Li, Ting

2013-08-13T23:59:59.000Z

149

Photodegradation and wavelength dependency of blue polymer light-emitting diode devices  

SciTech Connect (OSTI)

A systematic study of the wavelength dependency of the photodegradation of blue polymer light-emitting diodes is reported. Clearly two different regions can be distinguished, inside the absorption band, where the strongest and permanent photodegradation is found, and at wavelengths above the edge of absorption, where at least partially reversible photodegradation is observed. Irradiation experiments on samples with and without a cathode show the effect of the cathode-polymer interface and its contribution to the degradation mechanisms involved.

Colditz, H.J.O.; Kurt, R.; Buechel, M. [Royal Philips Electronics, Philips Research Laboratories Eindhoven, High Tech Campus 4 (WAG11), 5656 AE Eindhoven (Netherlands)

2005-12-19T23:59:59.000Z

150

A low-cost optical sensing device based on paired emitter-detector light emitting diodes. Analytica Chimica Acta 2006  

E-Print Network [OSTI]

A low power, high sensitivity, very low cost light emitting diode (LED) based device for intensity based light measurements is described. In this approach, a reverse-biased LED functioning as a photodiode, is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in us) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1(+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. this light intensity dependent discharge process has been applied to measuring concentrations of coloured solutions and a mathematical model developed based on the Beer-Lambert Law.

King-tong Lau; Susan Baldwin; Roderick Shepherd; William J. Yerazunis; Shinichi Izuo; Satoshi Ueyama; Dermont Diamond; Emitter-detector Leds; King-tong Lau; Susan Baldwin; Roderick Shepherd; William J; Shinichi Izuo; Satoshi Ueyama; Dermot Diamond

151

Ultraviolet emission from a multi-layer graphene/MgZnO/ZnO light-emitting diode  

SciTech Connect (OSTI)

We report on ultraviolet emission from a multi-layer graphene (MLG)/MgZnO/ZnO light-emitting diodes (LED). The p-type MLG and MgZnO in the MLG/MgZnO/ZnO LED are used as transparent hole injection and electron blocking layers, respectively. The current-voltage characteristics of the MLG/MgZnO/ZnO LED show that current transport is dominated by tunneling processes in the MgZnO barrier layer under forward bias conditions. The holes injected from p-type MLG recombine efficiently with the electrons accumulated in ZnO, and the MLG/MgZnO/ZnO LED shows strong ultraviolet emission from the band edge of ZnO and weak red-orange emission from the deep levels of ZnO.

Kang, Jang-Won; Choi, Yong-Seok; Goo Kang, Chang; Hun Lee, Byoung [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Kim, Byeong-Hyeok [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093-0407 (United States); Park, Seong-Ju, E-mail: sjpark@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

2014-02-03T23:59:59.000Z

152

Enhancement in light emission and electrical efficiencies of a silicon nanocrystal light-emitting diode by indium tin oxide nanowires  

SciTech Connect (OSTI)

We report an enhancement in light emission and electrical efficiencies of a Si nanocrystal (NC) light-emitting diode (LED) by employing indium tin oxide (ITO) nanowires (NWs). The formed ITO NWs (diameter?LED were significantly improved, which was attributed to an enhancement in the current spreading property due to densely interconnecting ITO NWs. In addition, light output power and wall-plug efficiency from the Si NC LED were enhanced by 45% and 38%, respectively. This was originated from an enhancement in the escape probability of the photons generated in the Si NCs due to multiple scatterings at the surface of ITO NWs acting as a light waveguide. We show here that the use of the ITO NWs can be very useful for realizing a highly efficient Si NC LED.

Huh, Chul, E-mail: chuh@etri.re.kr; Kim, Bong Kyu; Ahn, Chang-Geun; Kim, Sang-Hyeob [IT Convergence Technology Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 305-350 (Korea, Republic of); Choi, Chel-Jong [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2014-07-21T23:59:59.000Z

153

LED Retrofit Project in TSH Basement On July 14 2014, McMaster Facilities Services completed an energy conservation lighting  

E-Print Network [OSTI]

replaced with the new LED (light emitting diode) tubes. LEDs have better lighting quality, lower energy

Haykin, Simon

154

Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation  

SciTech Connect (OSTI)

We report on the direct patterning of two-dimensional periodic structures in GaN-based light-emitting diodes (LEDs) through laser interference ablation for the fast and reliable fabrication of periodic micro- and nano-structures aimed at enhancing light output. Holes arranged in a two-dimensional hexagonal lattice array having an opening size of 500?nm, depth of 50?nm, and a periodicity of 1??m were directly formed by three-beam laser interference without photolithography or electron-beam lithography processes. The laser-patterned LEDs exhibit an enhancement in light output power of 20% compared to conventional LEDs having a flat top surface without degradation of electrical and optical properties of the top p-GaN layer and the active region, respectively.

Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Yuan, Dajun; Guo, Rui [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Liu, Jianping [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125 (China); Asadirad, Mojtaba [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Kwon, Min-Ki [Department of Photonic Engineering, Chosun University, Seosuk-dong, Gwangju 501-759 (Korea, Republic of); Dupuis, Russell D. [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Das, Suman [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Department of Mechanical Engineering and Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204-4006 (United States)

2014-04-07T23:59:59.000Z

155

Interplay between multiple scattering, emission, and absorption of light in the phosphor of a white light-emitting diode  

E-Print Network [OSTI]

We study light transport in phosphor plates of white light-emitting diodes (LEDs). We measure the broadband diffuse transmission through phosphor plates of varying YAG:Ce$^{3+}$ density. We distinguish the spectral ranges where absorption, scattering, and re-emission dominate. Using diffusion theory, we derive the transport and absorption mean free paths from first principles. We find that both transport and absorption mean free paths are on the order of the plate thickness. This means that phosphors in commercial LEDs operate well within an intriguing albedo range around 0.7. We discuss how salient parameters that can be derived from first principles control the optical properties of a white LED.

Leung, V Y F; Tukker, T W; Mosk, A P; IJzerman, W L; Vos, W L

2013-01-01T23:59:59.000Z

156

Differential spectral responsivity measurement of photovoltaic detectors with a light-emitting-diode-based integrating sphere source  

SciTech Connect (OSTI)

We present an experimental realization of differential spectral responsivity measurement by using a light-emitting diode (LED)-based integrating sphere source. The spectral irradiance responsivity is measured by a Lambertian-like radiation field with a diameter of 40mm at the peak wavelengths of the 35 selectable LEDs covering a range from 280 to 1550nm. The systematic errors and uncertainties due to lock-in detection, spatial irradiance distribution, and reflection from the test detector are experimentally corrected or considered. In addition, we implemented a numerical procedure to correct the error due to the broad spectral bandwidth of the LEDs. The overall uncertainty of the DSR measurement is evaluated to be 2.2% (k=2) for Si detectors. To demonstrate its application, we present the measurement results of two Si photovoltaic detectors at different bias irradiance levels up to 120mW/cm{sup 2}.

Zaid, Ghufron; Park, Seung-Nam; Park, Seongchong; Lee, Dong-Hoon

2010-12-10T23:59:59.000Z

157

Electrical, optical, and material characterizations of blue InGaN light emitting diodes submitted to reverse-bias stress in water vapor condition  

SciTech Connect (OSTI)

In this paper, we investigate degradation of InGaN/GaN light emitting diodes (LEDs) under reverse-bias operations in water vapor and dry air. To examine failure origins, electrical characterizations including current-voltage, breakdown current profiles, optical measurement, and multiple material analyses were performed. Our findings indicate that the diffusion of indium atoms in water vapor can expedite degradation. Investigation of reverse-bias stress can help provide insight into the effects of water vapor on LEDs.

Chen, Hsiang, E-mail: hchen@ncnu.edu.tw; Chu, Yu-Cheng; Chen, Yun-Ti; Chen, Chian-You [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, No. 1, University Road, Puli, Nantou County 54561, Taiwan (China); Shei, Shih-Chang [Department of Electrical Engineering, National University of Tainan, No.33, Sec. 2, Shulin St., West Central Dist., Tainan City 70005, Taiwan (China)

2014-09-07T23:59:59.000Z

158

All-small-molecule efficient white organic light-emitting diodes by multi-layer blade coating  

E-Print Network [OSTI]

Letter All-small-molecule efficient white organic light-emitting diodes by multi-layer blade-molecule organic light-emitting diodes are fabricated by multi-layer blade coating on hot plate at 80 °C with hot.3 lm/W). Orange emitter iridium(III)bis (4-(4-t-butylphenyl) thie- no[3,2-c]pyridinato-N,C20

Meng, Hsin-Fei

159

Observation of enhanced visible and infrared emissions in photonic crystal thin-film light-emitting diodes  

SciTech Connect (OSTI)

Photonic crystals, in the form of closed-packed nano-pillar arrays patterned by nanosphere lithography, have been formed on the n-faces of InGaN thin-film vertical light-emitting diodes (LEDs). Through laser lift-off of the sapphire substrate, the thin-film LEDs conduct vertically with reduced dynamic resistances, as well as reduced thermal resistances. The photonic crystal plays a role in enhancing light extraction, not only at visible wavelengths but also at infrared wavelengths boosting heat radiation at high currents, so that heat-induced effects on internal quantum efficiencies are minimized. The observations are consistent with predictions from finite-difference time-domain simulations.

Cheung, Y. F.; Li, K. H.; Hui, R. S. Y.; Choi, H. W., E-mail: hwchoi@hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

2014-08-18T23:59:59.000Z

160

Organic Light Emitting Diodes Using a Ga:ZnO Anode  

SciTech Connect (OSTI)

We report the application of gallium doped zinc oxide (GZO) films as anodes in organic light emitting diodes (OLEDs). Pulsed laser deposited GZO films of differing Ga composition are examined. Bilayer OLEDs using GZO and indium tin oxide (ITO) anodes are then compared. Relative to ITO, the GZO anodes have slightly better sheet resistance and transparency in the visible spectral region. Device data suggest GZO results in more effective hole injection into an aromatic triamine hole transporting layer. Indium free anodes are expected toimprove OLED stability while lowering the cost per unit area, crucial for OLED based lighting applications.

Berry, J. J.; Ginley, D. S.; Burrows, Paul E.

2008-05-12T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Room temperature midinfrared electroluminescence from InSb/InAs quantum dot light emitting diodes  

SciTech Connect (OSTI)

Self-assembled InSb submonolayer quantum dots (QDs) in an InAs matrix have been grown by molecular beam epitaxy using Sb{sub 2} and As{sub 2} fluxes. The structures exhibit bright midinfrared photoluminescence up to room temperature. Intense room temperature electroluminescence with a peak at wavelength near 3.8 {mu}m was observed from p-i-n light emitting diode structures containing ten InSb submonolayer QD sheets inserted within the InAs active region.

Carrington, P. J.; Solov'ev, V. A.; Zhuang, Q.; Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Ivanov, S. V. [Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021 (Russian Federation)

2008-09-01T23:59:59.000Z

162

Temperature-dependent efficiency droop of blue InGaN micro-light emitting diodes  

SciTech Connect (OSTI)

Temperature-dependent trends in radiative and Auger recombination coefficients have been determined at different injection carrier concentrations using InGaN micro-light emitting diodes 40 ?m in diameter. The differential lifetime was obtained first from the measured modulation bandwidth and was then employed to calculate the carrier concentration in the quantum well active region. When the temperature increases, the carrier concentration increases, but both the radiative and Auger recombination coefficients decrease. In addition, the temperature dependence of radiative and Auger recombination coefficients is weaker at a higher injection carrier concentration, which is strongly related to phase space filling.

Tian, Pengfei; McKendry, Jonathan J. D.; Herrnsdorf, Johannes; Ferreira, Ricardo; Watson, Ian M.; Gu, Erdan, E-mail: erdan.gu@strath.ac.uk; Dawson, Martin D. [Institute of Photonics, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW (United Kingdom); Watson, Scott; Kelly, Anthony E. [School of Engineering, University of Glasgow, James Watt South Building, Glasgow G12 8LT (United Kingdom)

2014-10-27T23:59:59.000Z

163

LIGHT EMITTING DIODE (LED) TRAFFIC SIGNAL SURVEY RESULTS  

E-Print Network [OSTI]

Bernardino County Roseville Sebastopol West Covina San Diego County Ross Shasta Lake West Hollywood San

164

Demonstration Assessment of Light Emitting Diode (LED) Street Lighting,  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat Pump Models | Department1 Prepared1217 Release NotesFinal Report | Department of

165

Demonstration Assessment of Light-Emitting Diode (LED) Freezer Case  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: TopEnergy DOEDealing With the Issues of NuclearHighStatement| Department

166

Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract--In metal organic vapor phase epitaxy we developed  

E-Print Network [OSTI]

Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract-- In metal organic vapor phase epitaxy we developed GaInN/GaN quantum well material suitable for 500 ­ 580 nm light emitting diodes at longer wavelengths. Index Terms-- a-plane GaN, GaInN, Green light emitting diode, m-plane GaN I

Wetzel, Christian M.

167

ZnO PN Junctions for Highly-Efficient, Low-Cost Light Emitting Diodes  

SciTech Connect (OSTI)

By 2015, the US Department of Energy has set as a goal the development of advanced solid state lighting technologies that are more energy efficient, longer lasting, and more cost-effective than current technology. One approach that is most attractive is to utilize light-emitting diode technologies. Although III-V compound semiconductors have been the primary focus in pursuing this objective, ZnO-based materials present some distinct advantages that could yield success in meeting this objective. As with the nitrides, ZnO is a direct bandgap semiconductor whose gap energy (3.2 eV) can be tuned from 3.0 to 4 eV with substitution of Mg for higher bandgap, Cd for lower bandgap. ZnO has an exciton binding energy of 60 meV, which is larger than that for the nitrides, indicating that it should be a superior light emitting semiconductor. Furthermore, ZnO thin films can be deposited at temperatures on the order of 400-600 C, which is significantly lower than that for the nitrides and should lead to lower manufacturing costs. It has also been demonstrated that functional ZnO electronic devices can be fabricated on inexpensive substrates, such as glass. Therefore, for the large-area photonic application of solid state lighting, ZnO holds unique potential. A significant impediment to exploiting ZnO in light-emitting applications has been the absence of effective p-type carrier doping. However, the recent realization of acceptor-doped ZnO material overcomes this impediment, opening the door to ZnO light emitting diode development In this project, the synthesis and properties of ZnO-based pn junctions for light emitting diodes was investigated. The focus was on three issues most pertinent to realizing a ZnO-based solid state lighting technology, namely (1) achieving high p-type carrier concentrations in epitaxial and polycrystalline films, (2) realizing band edge emission from pn homojunctions, and (3) investigating pn heterojunction constructs that should yield efficient light emission. The project engaged established expertise at the University of Florida in ZnO film growth (D. Norton), device fabrication (F. Ren) and wide bandgap photonics (S. Pearton). It addressed p-type doping and junction formation in (Zn,Mg)O alloy thin films. The project employed pulsed laser deposition for film growth. The p-type dopant of interest was primarily phosphorus, given the recent results in our laboratory and elsewhere that this anions can yield p-type ZnO-based materials. The role of Zn interstitials, oxygen vacancies, and/or hydrogen complexes in forming compensating shallow donor levels imposes the need to simultaneously consider the role of in situ and post-growth processing conditions. Temperature-dependent Hall, Seebeck, C-V, and resistivity measurements was used to determine conduction mechanisms, carrier type, and doping. Temperature-dependent photoluminescence was used to determine the location of the acceptor level, injection efficiency, and optical properties of the structures. X-ray diffraction will used to characterize film crystallinity. Using these materials, the fabrication and characterization of (Zn,Mg)O pn homojunction and heterojunction devices was pursued. Electrical characterization of the junction capacitance and I-V behavior was used to extract junction profile and minority carrier lifetime. Electroluminescence from biased junctions was the primary property of interest.

David P. Norton; Stephen Pearton; Fan Ren

2007-09-30T23:59:59.000Z

168

Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes  

SciTech Connect (OSTI)

We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)] [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2013-01-28T23:59:59.000Z

169

Highly efficient greenish-blue platinum-based phosphorescent organic light-emitting diodes on a high triplet energy platform  

SciTech Connect (OSTI)

We have demonstrated high-efficiency greenish-blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a dimesitylboryl-functionalized C^N chelate Pt(II) phosphor, Pt(m-Bptrz)(t-Bu-pytrz-Me). Using a high triplet energy platform and optimized double emissive zone device architecture results in greenish-blue PHOLEDs that exhibit an external quantum efficiency of 24.0% and a power efficiency of 55.8?lm/W. This record high performance is comparable with that of the state-of-the-art Ir-based sky-blue organic light-emitting diodes.

Chang, Y. L., E-mail: yilu.chang@mail.utoronto.ca; Gong, S., E-mail: sgong@chem.utoronto.ca; White, R.; Lu, Z. H., E-mail: zhenghong.lu@utoronto.ca [Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, Ontario M5S 3E4 (Canada); Wang, X.; Wang, S., E-mail: wangs@chem.queensu.ca [Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6 (Canada); Yang, C. [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

2014-04-28T23:59:59.000Z

170

Journal of Crystal Growth 298 (2007) 272275 Dislocation analysis in homoepitaxial GaInN/GaN light emitting  

E-Print Network [OSTI]

of GaInN/GaN-based light emitting diodes (LED) on quasi-bulk GaN with an atomically flat polished were much improved. The optical output power of the light emitting diode increased by more than one. Cathodoluminescence; A1. Threading dislocation density; A2. Homoepitaxial growth; B1. GaInN; B3. Light emitting diode

Wetzel, Christian M.

171

Green cubic GaInN/GaN light-emitting diode on microstructured silicon (100)  

SciTech Connect (OSTI)

GaInN/GaN light-emitting diodes free of piezoelectric polarization were prepared on standard electronic-grade Si(100) substrates. Micro-stripes of GaN and GaInN/GaN quantum wells in the cubic crystal structure were grown on intersecting (111) planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. Crystal phases were identified in electron back-scattering diffraction. A cross-sectional analysis reveals a cubic structure virtually free of line defects. Electroluminescence over 20 to 100??A is found fixed at 487?nm (peak), 516?nm (dominant). Such structures therefore should allow higher efficiency, wavelength-stable light emitters throughout the visible spectrum.

Stark, Christoph J. M.; Detchprohm, Theeradetch; Wetzel, Christian, E-mail: wetzel@ieee.org [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Future Chips Constellation, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Lee, S. C.; Brueck, S. R. J. [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)] [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States); Jiang, Y.-B. [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)] [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2013-12-02T23:59:59.000Z

172

Ultrastrong light-matter coupling in electrically doped microcavity organic light emitting diodes  

SciTech Connect (OSTI)

The coupling of the electromagnetic field with an electronic transition gives rise, for strong enough light-matter interactions, to hybrid states called exciton-polaritons. When the energy exchanged between light and matter becomes a significant fraction of the material transition energy an extreme optical regime called ultrastrong coupling (USC) is achieved. We report a microcavity embedded p-i-n monolithic organic light emitting diode working in USC, employing a thin film of squaraine dye as active layer. A normalized coupling ratio of 30% has been achieved at room temperature. These USC devices exhibit a dispersion-less angle-resolved electroluminescence that can be exploited for the realization of innovative optoelectronic devices. Our results may open the way towards electrically pumped polariton lasers.

Mazzeo, M., E-mail: marco.mazzeo@unisalento.it [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); Genco, A. [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); Gambino, S. [NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); CBN, Istituto Italiano Tecnologia, Via Barsanti 1, 73010 Lecce (Italy); Ballarini, D.; Mangione, F.; Sanvitto, D. [NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); Di Stefano, O.; Patanè, S.; Savasta, S. [Dipartimento di Fisica e Scienze della Terra, Università di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina (Italy); Gigli, G. [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); CBN, Istituto Italiano Tecnologia, Via Barsanti 1, 73010 Lecce (Italy)

2014-06-09T23:59:59.000Z

173

Room-temperature spin-polarized organic light-emitting diodes with a single ferromagnetic electrode  

SciTech Connect (OSTI)

In this paper, we demonstrate the concept of a room-temperature spin-polarized organic light-emitting diode (Spin-OLED) structure based on (i) the deposition of an ultra-thin p-type organic buffer layer on the surface of the ferromagnetic electrode of the Spin-OLED and (ii) the use of oxygen plasma treatment to modify the surface of that electrode. Experimental results demonstrate that the brightness of the developed Spin-OLED can be increased by 110% and that a magneto-electroluminescence of 12% can be attained for a 150?mT in-plane magnetic field, at room temperature. This is attributed to enhanced hole and room-temperature spin-polarized injection from the ferromagnetic electrode, respectively.

Ding, Baofu, E-mail: b.ding@ecu.edu.au; Alameh, Kamal, E-mail: k.alameh@ecu.edu.au [Electron Science Research Institute, Edith Cowan University, 270 Joondalup Drive, Joondalup WA 6027 Australia (Australia); Song, Qunliang [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China)

2014-05-19T23:59:59.000Z

174

Origin of InGaN/GaN light-emitting diode efficiency improvements using tunnel-junction-cascaded active regions  

SciTech Connect (OSTI)

This Letter investigates the efficiency enhancement achieved by tunnel junction insertion into the InGaN/GaN multi-quantum well (MQW) active region of blue light emitting diodes (LEDs). The peak quantum efficiency of such LED exceeds 100%, but the maximum wall-plug efficiency (WPE) hardly changes. However, due to the increased bias, the WPE peaks at much higher input power, i.e., the WPE droop is significantly delayed, and the output power is strongly enhanced. The main physical reason for this improvement lies in the non-uniform vertical carrier distribution typically observed within InGaN MQWs.

Piprek, Joachim, E-mail: piprek@nusod.org [NUSOD Institute LLC, P.O. Box 7204, Newark, Delaware 19714 (United States)

2014-02-03T23:59:59.000Z

175

Angular distribution of polarized spontaneous emissions and its effect on light extraction behavior in InGaN-based light emitting diodes  

SciTech Connect (OSTI)

Angular intensity distributions of differently polarized light sources in multiple quantum wells (MQWs) and their effects on extraction behavior of spontaneous emission from light emitting diode (LED) chips have been studied. Theoretical calculation based on k·p approximation, ray tracing simulation and angular electroluminescence measurement were applied in this work. It is found that the electron-hole recombination in the InGaN MQWs produces a spherical distribution of an s-polarized source and a dumbbell-shaped p-polarized source. Light rays from different polarized sources experience different extraction processes, determining the polarization degree of electro-luminescence and extraction efficiency of LEDs.

Yuan, Gangcheng; Chen, Xinjuan; Yu, Tongjun, E-mail: tongjun@pku.edu.cn; Lu, Huimin; Chen, Zhizhong; Kang, Xiangning; Wu, Jiejun; Zhang, Guoyi [State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

2014-03-07T23:59:59.000Z

176

Top-emitting Organic Light-Emitting Diode with a Cap Layer Chengfeng Qiu, Huajun Peng, Haiying Chen, Zhilang Xie,  

E-Print Network [OSTI]

, Kowloon, Hong Kong, China ABSTRACT For top emitting Organic Light-Emitting Diodes (OLED), the study of top layer is very important aiming to acquire good device performance. In this report, Pt as anode for Cu coated on glass as anode, copper (II) phthalocyanine (CuPc) as organic buffer layer, N,N'- diphenyl

Kwok, Hoi S.

177

Effect of carbazoleoxadiazole excited-state complexes on the efficiency of dye-doped light-emitting diodes  

E-Print Network [OSTI]

Effect of carbazole­oxadiazole excited-state complexes on the efficiency of dye-doped light a profound effect on the external quantum efficiency of dye-doped organic light-emitting diodes employing the matrix to the dye. Single-layer devices doped with either coumarin 47 C47 , coumarin 6 C6 , or nile red

178

Solvent-enhanced dye diffusion in polymer thin films for color tuning of organic light-emitting diodes  

E-Print Network [OSTI]

Solvent-enhanced dye diffusion in polymer thin films for color tuning of organic light; accepted for publication 27 February 2001 A method of solvent-enhanced dye diffusion in polymer films for organic light-emitting diode OLED application is introduced. After an initial dye transfer from a dye

179

Solution Processed Tungsten Oxide Interfacial Layer for Efficient Hole-Injection in Quantum Dot Light-Emitting Diodes  

E-Print Network [OSTI]

2/2014 Solution Processed Tungsten Oxide Interfacial Layer for Efficient Hole-Injection in Quantum Layer for Efficient Hole-Injection in Quantum Dot Light- Emitting Diodes Xuyong Yang, Evren Mutlugun-based devices, the organic interfacial buffer layers have inferior thermal stability. Efforts to replace PEDOT

Demir, Hilmi Volkan

180

WHITE ORGANIC LIGHT-EMITTING DIODES USING 1,1,2,3,4,5-HEXAPHENYLSILOLE (HPS) AS GREENISH-BLUE EMITTER  

E-Print Network [OSTI]

WHITE ORGANIC LIGHT-EMITTING DIODES USING 1,1,2,3,4,5- HEXAPHENYLSILOLE (HPS) AS GREENISH, Hong Kong, P. R. China Abstract White organic light-emitting diodes (WOLEDs) with the structure of ITO emitter and the 1,1,2,3,4,5- hexaphenylsilole (HPS) layer was used as the greenish- blue emitter. White

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Series Input Modular Architecture for Driving Multiple LEDs  

E-Print Network [OSTI]

, where each cell drives four 700 mA LEDs. Keywords ­ solid-state lighting, light emitting diodes, LED have been achieved over the past decade in solid state light emitting diodes (LEDs), leading to high

182

Performance enhancement of organic light-emitting diodes by chlorine plasma treatment of indium tin oxide  

SciTech Connect (OSTI)

The characteristics of green phosphorescent organic light-emitting diodes (OLEDs) fabricated on ITO/glass substrates pretreated with low-energy O{sub 2} and Cl{sub 2} plasma were compared. At 20 mA/cm{sup 2}, the OLEDs with O{sub 2} and Cl{sub 2} plasma-treated indium tin oxide (ITO) had voltages of 9.6 and 7.6 eV, and brightness of 9580 and 12380 cd/m{sup 2}, respectively. At {approx}10{sup 4} cd/m{sup 2}, the latter had a 30% higher external quantum efficiency and a 74% higher power efficiency. Photoelectron spectroscopies revealed that Cl{sub 2} plasma treatment created stable In-Cl bonds and raised the work function of ITO by up to 0.9 eV. These results suggest that the better energy level alignment at the chlorinated ITO/organic interface enhances hole injection, leading to more efficient and more reliable operation of the OLEDs. The developed plasma chlorination process is very effective for surface modification of ITO and compatible with the fabrication of various organic electronics.

Cao, X. A.; Zhang, Y. Q. [Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, West Virginia 26506 (United States)

2012-04-30T23:59:59.000Z

183

White organic light-emitting diodes with an ultra-thin premixed emitting layer  

E-Print Network [OSTI]

We described an approach to achieve fine color control of fluorescent White Organic Light-Emitting Diodes (OLED), based on an Ultra-thin Premixed emitting Layer (UPL). The UPL consists of a mixture of two dyes (red-emitting 4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene or fvin and green-emitting 4-di(4'-tert-butylbiphenyl-4-yl)aminobenzaldehyde or fcho) premixed in a single evaporation cell: since these two molecules have comparable structures and similar melting temperatures, a blend can be evaporated, giving rise to thin films of identical and reproducible composition compared to those of the pre-mixture. The principle of fine color tuning is demonstrated by evaporating a 1-nm-thick layer of this blend within the hole-transport layer (4,4'-bis[N-(1-naphtyl)-N-phenylamino]biphenyl (\\alpha-NPB)) of a standard fluorescent OLED structure. Upon playing on the position of the UPL inside the hole-transport layer, as well as on the premix composition, two independent parameters are available to finel...

Jeon, T; Tondelier, Denis; Bonnassieux, Yvan; Forget, Sebastien; Chenais, Sebastien; Ishow, Elena

2014-01-01T23:59:59.000Z

184

Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction  

SciTech Connect (OSTI)

Very uniform 2 {micro}m-pitch square microlens arrays ({micro}LAs), embossed on the blank glass side of an indium-tin-oxide (ITO)-coated 1.1 mm-thick glass, are used to enhance light extraction from organic light-emitting diodes (OLEDs) by {approx}100%, significantly higher than enhancements reported previously. The array design and size relative to the OLED pixel size appear to be responsible for this enhancement. The arrays are fabricated by very economical soft lithography imprinting of a polydimethylsiloxane (PDMS) mold (itself obtained from a Ni master stamp that is generated from holographic interference lithography of a photoresist) on a UV-curable polyurethane drop placed on the glass. Green and blue OLEDs are then fabricated on the ITO to complete the device. When the {mu}LA is {approx}15 x 15 mm{sup 2}, i.e., much larger than the {approx}3 x 3 mm{sup 2} OLED pixel, the electroluminescence (EL) in the forward direction is enhanced by {approx}100%. Similarly, a 19 x 25 mm{sup 2} {mu}LA enhances the EL extracted from a 3 x 3 array of 2 x 2 mm{sup 2} OLED pixels by 96%. Simulations that include the effects of absorption in the organic and ITO layers are in accordance with the experimental results and indicate that a thinner 0.7 mm thick glass would yield a {approx}140% enhancement.

Park, Joong-Mok; Gan, Zhengqing; Leung, Wai Y.; Liu, Rui; Ye, Zhuo; Constant, Kristen; Shinar, Joseph; Shinar, Ruth; Ho, Kai-Ming

2011-06-06T23:59:59.000Z

185

A Polysilicon Active Matrix Organic Light Emitting Diode Display with Integrated Drivers R.M.A. Dawson, Z. Shen, D.A. Furst, S. Connor, J. Hsu, M.G. Kane, R.G. Stewart, A. Ipri  

E-Print Network [OSTI]

A Polysilicon Active Matrix Organic Light Emitting Diode Display with Integrated Drivers R.S.A. Abstract The design of an active matrix organic light emitting diode (AMOLED) display using a polysilicon. Introduction Organic light emitting diodes (OLEDs) are presently of great interest due to their potential

186

Optical Simulation of Top-emitting Organic Light Emitting Diodes H. J. Peng, C.F. Qiu, Z. L. Xie, H. Y. Chen, M. Wong and H. S. Kwok  

E-Print Network [OSTI]

8.3.3-89 Optical Simulation of Top-emitting Organic Light Emitting Diodes H. J. Peng, C.F. Qiu, Z the optical effects for the top-emitting organic light emitting diodes. The optical performance of the devices with experiments Keywords: Top-emitting organic light emitting diode, optical modeling, microcavity INTRODUCTION

Kwok, Hoi S.

187

Milliwatt operation of AlGaN-based single-quantum-well light emitting diode in the ultraviolet region  

SciTech Connect (OSTI)

By introducing a single-quantum-well active layer and a high-Al-content carrier blocking layer, the output power of an AlGaN-based ultraviolet light-emitting diode has been improved by one order of magnitude. Optical output of 1 mW was achieved at the emission peak wavelength of 341{endash}343 nm. {copyright} 2001 American Institute of Physics.

Nishida, Toshio; Saito, Hisao; Kobayashi, Naoki

2001-06-18T23:59:59.000Z

188

Growth and characterizations of GaN micro-rods on graphene films for flexible light emitting diodes  

SciTech Connect (OSTI)

We report the growth of GaN micro-rods and coaxial quantum-well heterostructures on graphene films, together with structural and optical characterization, for applications in flexible optical devices. Graphene films were grown on Cu foil by means of chemical vapor deposition, and used as the substrates for the growth of the GaN micro-rods, which were subsequently transferred onto SiO{sub 2}/Si substrates. Highly Si-doped, n-type GaN micro-rods were grown on the graphene films using metal–organic chemical vapor deposition. The growth and vertical alignment of the GaN micro-rods, which is a critical factor for the fabrication of high-performance light-emitting diodes (LEDs), were characterized using electron microscopy and X-ray diffraction. The GaN micro-rods exhibited promising photoluminescence characteristics for optoelectronic device applications, including room-temperature stimulated emission. To fabricate flexible LEDs, In{sub x}Ga{sub 1–x}N/GaN multiple quantum wells and a p-type GaN layer were deposited coaxially on the GaN micro-rods, and transferred onto Ag-coated polymer substrates using lift-off. Ti/Au and Ni/Au metal layers were formed to provide electrical contacts to the n-type and p-type GaN regions, respectively. The micro-rod LEDs exhibited intense emission of visible light, even after transfer onto the flexible polymer substrate, and reliable operation was achieved following numerous cycles of mechanical deformation.

Chung, Kunook; Beak, Hyeonjun; Tchoe, Youngbin; Oh, Hongseok; Yi, Gyu-Chul, E-mail: gcyi@snu.ac.kr [Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Yoo, Hyobin; Kim, Miyoung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2014-09-01T23:59:59.000Z

189

Development of monolithic CMOS-compatible visible light emitting diode arrays on silicon  

E-Print Network [OSTI]

The synergies associated with integrating Si-based CMOS ICs and III-V-material-based light-emitting devices are very exciting and such integration has been an active area of research and development for quite some time ...

Chilukuri, Kamesh

2006-01-01T23:59:59.000Z

190

Development and Utilization of Host Materials for White Phosphorescent Organic Light-Emitting Diodes  

SciTech Connect (OSTI)

Our project was primarily focused on the MYPP 2015 goal for white phosphorescent organic devices (PhOLEDs or phosphorescent organic light-emitting diodes) for solid-state lighting with long lifetimes and high efficiencies. Our central activity was to synthesize and evaluate a new class of host materials for blue phosphors in the PhOLEDs, known to be a weak link in the device operating lifetime. The work was a collaborative effort between three groups, one primarily responsible for chemical design and characterization (Chen), one primarily responsible for device development (Tang) and one primarily responsible for mechanistic studies and degradation analysis (Rothberg). The host materials were designed with a novel architecture that chemically links groups with good ability to move electrons with those having good ability to move “holes” (positive charges), the main premise being that we could suppress the instability associated with physical separation and crystallization of the electron conducting and hole conducting materials that might cause the devices to fail. We found that these materials do prevent crystallization and that this will increase device lifetimes but that efficiencies were reduced substantially due to interactions between the materials creating new low energy “charge transfer” states that are non-luminescent. Therefore, while our proposed strategy could in principle improve device lifetimes, we were unable to find a materials combination where the efficiency was not substantially compromised. In the course of our project, we made several important contributions that are peripherally related to the main project goal. First, we were able to prepare the proposed new family of materials and develop synthetic routes to make them efficiently. These types of materials that can transport both electrons and holes may yet have important roles to play in organic device technology. Second we developed an important new method for controlling the deposition profile of material so that arbitrary concentration gradients can be implemented in layers with mixed composition. These concentration profiles are known to increase device efficiency and longevity and we confirmed that experimentally. Third, we investigated a new method for analyzing degradation in devices using mass spectrometry to look for degradation products. We showed that these methods are not simple to interpret unambiguously and need to be used with caution.

Tang, Ching; Chen, Shaw

2013-05-31T23:59:59.000Z

191

Analysis of the causes of the decrease in the electroluminescence efficiency of AlGaInN light-emitting-diode heterostructures at high pumping density  

SciTech Connect (OSTI)

The study is devoted to theoretical explanation of a decrease in the electroluminescence efficiency as the pump current increases, which is characteristic of light-emitting-diode (LED) heterostructures based on AlInGaN. Numerical simulation shows that the increase in the external quantum efficiency at low current densities J {approx} 1 A/cm{sup 2} is caused by the competition between radiative and nonradiative recombination. The decrease in the quantum efficiency at current densities J > 1 A/cm{sup 2} is caused by a decrease in the efficiency of hole injection into the active region. It is shown that the depth of the acceptor energy level in the AlGaN emitter, as well as low electron and hole mobilities in the p-type region, plays an important role in this effect. A modified LED heterostructure is suggested in which the efficiency decrease with the pump current should not occur.

Rozhansky, I. V., E-mail: igor@quantum.ioffe.ru; Zakheim, D. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2006-07-15T23:59:59.000Z

192

Light-extraction enhancement in GaN-based light-emitting diodes using grade-refractive-index amorphous titanium oxide films with porous structures  

SciTech Connect (OSTI)

Amorphous titanium oxide (a-TiO{sub x}:OH) films prepared by plasma-enhanced chemical-vapor deposition at 200 and 25 deg. C are in turn deposited onto the GaN-based light-emitting diode (LED) to enhance the associated light extraction efficiency. The refractive index, porosity, and photocatalytic effect of the deposited films are correlated strongly with the deposition temperatures. The efficiency is enhanced by a factor of {approx}1.31 over that of the uncoated LEDs and exhibited an excellent photocatalytic property after an external UV light irradiation. The increase in the light extraction is related to the reduction in the Fresnel transmission loss and the enhancement of the light scattering into the escape cone by using the graded-refractive-index a-TiO{sub x}:OH film with porous structures.

Liu, D.-S.; Lin, T.-W.; Huang, B.-W.; Juang, F.-S.; Lei, P.-H. [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei 63201, Taiwan (China); Hu, C.-Z. [Chilin Technology Co. Ltd., Tainan County 71758, Taiwan (China)

2009-04-06T23:59:59.000Z

193

p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas  

SciTech Connect (OSTI)

Here, GaN/Al{sub x}Ga{sub 1-x}N heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional hole gas (3DHG). The existence of the 3DHG is confirmed by capacitance-voltage measurements. Based on this design, a p-doping-free InGaN/GaN light-emitting diode (LED) driven by the 3DHG is proposed and grown using MOCVD. The electroluminescence, which is attributed to the radiative recombination of injected electrons and holes in InGaN/GaN quantum wells, is observed from the fabricated p-doping-free devices. These results suggest that the 3DHG can be an alternative hole source for InGaN/GaN LEDs besides common Mg dopants.

Zhang, Zi-Hui; Tiam Tan, Swee; Kyaw, Zabu; Liu, Wei; Ji, Yun; Ju, Zhengang; Zhang, Xueliang [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore) [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Wei Sun, Xiao, E-mail: EXWSUN@ntu.edu.sg [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electronics and Electrical Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Volkan Demir, Hilmi, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electrical and Electronics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey); Department of Physics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey)

2013-12-23T23:59:59.000Z

194

Further reduction of efficiency droop effect by adding a lower-index dielectric interlayer in a surface plasmon coupled blue light-emitting diode with surface metal nanoparticles  

SciTech Connect (OSTI)

Further reduction of the efficiency droop effect and further enhancements of internal quantum efficiency (IQE) and output intensity of a surface plasmon coupled, blue-emitting light-emitting diode (LED) by inserting a dielectric interlayer (DI) of a lower refractive index between p-GaN and surface Ag nanoparticles are demonstrated. The insertion of a DI leads to a blue shift of the localized surface plasmon (LSP) resonance spectrum and increases the LSP coupling strength at the quantum well emitting wavelength in the blue range. With SiO{sub 2} as the DI, a thinner DI leads to a stronger LSP coupling effect, when compared with the case of a thicker DI. By using GaZnO, which is a dielectric in the optical range and a good conductor under direct-current operation, as the DI, the LSP coupling results in the highest IQE, highest LED output intensity, and weakest droop effect.

Lin, Chun-Han; Su, Chia-Ying; Chen, Chung-Hui; Yao, Yu-Feng; Shih, Pei-Ying; Chen, Horng-Shyang; Hsieh, Chieh; Kiang, Yean-Woei, E-mail: ywkiang@ntu.edu.tw; Yang, C. C., E-mail: ccycc@ntu.edu.tw [Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kuo, Yang [Department of Energy and Refrigerating Air-Conditioning Engineering, Tung Nan University, 152 Beishen Road, Section 3, New Taipei City, 22202 Taiwan (China)

2014-09-08T23:59:59.000Z

195

GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition  

SciTech Connect (OSTI)

Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300?°C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

Xu, Kun; Xu, Chen, E-mail: xuchen58@bjut.edu.cn; Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China)] [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Xie, Yiyang [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China)] [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China); Sun, Jie, E-mail: jie.sun@chalmers.se [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China) [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Mikroteknologi och Nanovetenskap, Chalmers Tekniska Högskola AB, Göteborg 41296 (Sweden)

2013-11-25T23:59:59.000Z

196

2014-06-18 Issuance: Test Procedure for Integrated Light-Emitting Diode Lamps; Supplemental Notice of Proposed Rulemaking  

Broader source: Energy.gov [DOE]

This document is a pre-publication Federal Register Supplemental Notice of Proposed Rulemaking regarding Test Procedures for Integrated Light-Emitting Diode Lamps, as issued by the Deputy Assistant Secretary for Energy Efficiency on June 18, 2014. Though it is not intended or expected, should any discrepancy occur between the document posted here and the document published in the Federal Register, the Federal Register publication controls. This document is being made available through the Internet solely as a means to facilitate the public's access to this document.

197

Modeling of temperature and excitation dependences of efficiency in an InGaN light-emitting diode  

E-Print Network [OSTI]

The changes in excitation dependence of efficiency with temperature is modeled for a wurtzite InGaN light-emitting diode. The model incorporates bandstructure changes with carrier density arising from screening of quantum-confined Stark effect. Bandstructure is computed by solving Poisson and k.p equations in the envelop approximation. The information is used in a dynamical model for populations in momentum-resolved electron and hole states. Application of the approach shows the interplay of quantum-well and barrier emissions giving rise to shape changes in efficiency versus current density with changing temperature, as observed in some experiments.

Chow, Weng W

2013-01-01T23:59:59.000Z

198

Influences of excitation-dependent bandstructure changes on InGaN light-emitting diode efficiency  

E-Print Network [OSTI]

Bandstructure properties in wurtzite quantum wells can change appreciably with changing carrier density because of screening of quantum-confined Stark effect. An approach for incorporating these changes in an InGaN light-emitting-diode model is described. Bandstructure is computed for different carrier densities by solving Poisson and k\\cdotp equations in the envelop approximation. The information is used as input in a dynamical model for populations in momentum-resolved electron and hole states. Application of the approach is illustrated by modeling device internal quantum efficiency as a function of excitation.

Chow, Weng W

2011-01-01T23:59:59.000Z

199

Driving conditions dependence of magneto-electroluminescence in tri-(8-hydroxyquinoline)-aluminum based organic light emitting diodes  

E-Print Network [OSTI]

we investigated the magneto-electroluminescence (MEL) in tri-(8-hydroxyquinoline)-aluminum based organic light-emitting diodes (OLEDs) through the steady-state and transient method simultaneously. The MELs show the great different behaviors when we turn the driving condition from a constant voltage to a pulse voltage. For devices driven by the constant voltage, the MELs are similar with the literature data; for devices driven by the pulse voltage, the MELs are quite different, they firstly increase to a maximum then decrease as the magnetic field increases continuously. Negative MELs can be seen when both the magnetic field and driving voltage are high enough.

Peng, Qiming; Li, Xianjie; Li, Mingliang; Li, Feng

2011-01-01T23:59:59.000Z

200

MoO3 as combined hole injection layer and tapered spacer in combinatorial multicolor microcavity organic light emitting diodes  

SciTech Connect (OSTI)

Multicolor microcavity ({mu}C) organic light-emitting diode (OLED) arrays were fabricated simply by controlling the hole injection and spacer MoO{sub 3} layer thickness. The normal emission was tunable from {approx}490 to 640 nm and can be further expanded. A compact, integrated spectrometer with two-dimensional combinatorial arrays of {mu}C OLEDs was realized. The MoO{sub 3} yields more efficient and stable devices, revealing a new breakdown mechanism. The pixel current density reaches {approx}4 A/cm{sup 2} and a maximal normal brightness {approx}140 000 Cd/m{sup 2}, which improves photoluminescence-based sensing and absorption measurements.

Liu, R.; Xu, Chun; Biswas, Rana; Shinar, Joseph; Shinar, Ruth

2011-09-01T23:59:59.000Z

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201

DARPA Soldier Self Care: Rapid Healing of Laser Eye Injuries with Light Emitting Diode Technology  

E-Print Network [OSTI]

RGC, retinal ganglion cell; TTX, tetrodotoxin. Photobiomodulation by light in the red to near infrared range (630-1000 nm) using low energy lasers or lightemitting diode (LED) arrays has been shown to accelerate wound healing, improve recovery from ischemic injury and attenuate degeneration in the injured optic nerve. At the cellular level, photoirradiation at low fluences can generate significant biological effects including cellular proliferation and the release of growth factors from cells. Mitochondrial cytochromes have been postulated as photoacceptors for red to near-infrared (NIR) light energy and reactive oxygen species or mitochondrial redox changes have been advanced as potential mediators of the biological effects of this light. We hypothesize that the therapeutic effects of red to near infrared light result, in part, from intracellular signaling mechanisms triggered by the interaction of NIR light with the mitochondrial photoacceptor

Harry T. Whelan; Margaret T. T. Wong-riley, Ph.D.; Janis T. Eells, Ph.D.; James N. Verhoeve, Ph.D.; Rina Das, Ph.D.; Marti Jett, Ph.D.

202

Organic Light-Emitting Diodes (OLEDs) and Optically-Detected Magnetic Resonance (ODMR) studies on organic materials  

SciTech Connect (OSTI)

Organic semiconductors have evolved rapidly over the last decades and currently are considered as the next-generation technology for many applications, such as organic light-emitting diodes (OLEDs) in flat-panel displays (FPDs) and solid state lighting (SSL), and organic solar cells (OSCs) in clean renewable energy. This dissertation focuses mainly on OLEDs. Although the commercialization of the OLED technology in FPDs is growing and appears to be just around the corner for SSL, there are still several key issues that need to be addressed: (1) the cost of OLEDs is very high, largely due to the costly current manufacturing process; (2) the efficiency of OLEDs needs to be improved. This is vital to the success of OLEDs in the FPD and SSL industries; (3) the lifetime of OLEDs, especially blue OLEDs, is the biggest technical challenge. All these issues raise the demand for new organic materials, new device structures, and continued lower-cost fabrication methods. In an attempt to address these issues, we used solution-processing methods to fabricate highly efficient small molecule OLEDs (SMOLEDs); this approach is costeffective in comparison to the more common thermal vacuum evaporation. We also successfully made efficient indium tin oxide (ITO)-free SMOLEDs to further improve the efficiency of the OLEDs. We employed the spin-dependent optically-detected magnetic resonance (ODMR) technique to study the luminescence quenching processes in OLEDs and organic materials in order to understand the intrinsic degradation mechanisms. We also fabricated polymer LEDs (PLEDs) based on a new electron-accepting blue-emitting polymer and studied the effect of molecular weight on the efficiency of PLEDs. All these studies helped us to better understand the underlying relationship between the organic semiconductor materials and the OLEDs’ performance, and will subsequently assist in further enhancing the efficiency of OLEDs. With strongly improved device performance (in addition to other OLEDs' attributes such as mechanical flexibility and potential low cost), the OLED technology is promising to successfully compete with current technologies, such as LCDs and inorganic LEDs.

Cai, Min

2011-11-30T23:59:59.000Z

203

Determination of the emission zone in a single-layer polymer light-emitting diode through optical measurements  

SciTech Connect (OSTI)

We study the emission zone in a single-layer polymer light-emitting diode. The emission zone is found by studying the angular distribution of the electroluminescence. The emission is modeled by accounting for optical interference. We account for birefringence of the anode layer in our model. The active polymer was, however, found to be isotropic. The anode consists of a single-layer of the conducting polymer complex poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonate) (PEDOT-PSS), with enhanced conductivity. As a cathode we use plain aluminum. By using only PEDOT-PSS we avoid having a thin metal layer or indium-tin-oxide as the anode in the path of the escaping light. The active material is a substituted polythiophene with excellent film forming properties. A comparison between the experimental and calculated angular distribution of light emission from a single-layered polymer light-emitting diode was shown to be in good agreement for the spectral region studied. By assuming a distribution of the emission zone, we deduce the position as well as the width of the zone. {copyright} 2001 American Institute of Physics.

Granlund, Thomas; Pettersson, Leif A. A.; Inganas, Olle

2001-06-01T23:59:59.000Z

204

Enhancement of hole injection using O{sub 2} plasma-treated Ag anode for top-emitting organic light-emitting diodes  

SciTech Connect (OSTI)

We report the enhancement of hole injection using AgO{sub x} layer between Ag anode and 4,4{sup '}-bis[N-(1-naphtyl)-N-phenyl-amino]biphenyl in top-emitting organic light-emitting diode (OLED). The turn-on voltage of OLEDs decreased from 17 to 7 V as Ag changed to AgO{sub x} by the surface treatment using O{sub 2} plasma. Synchrotron radiation photoelectron spectroscopy results showed that the work function increased about 0.4 eV by the O{sub 2} plasma treatment. This led to the decrease of the energy barrier for hole injection, reducing the turn-on voltage of OLEDs.

Ho, Won Choi; Soo, Young Kim; Kim, Ki-Beom; Tak, Yoon-Heung; Lee, Jong-Lam [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Korea (Korea, Republic of); LG Electronics Inc., Kumi, Kyungbuk, 730-030 (Korea, Republic of); Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784 (Korea, Republic of)

2005-01-03T23:59:59.000Z

205

3.2: Invited Paper: Biopolymers in Light Emitting Devices Andrew J. Steckl , Joshua A. Hagen, Zhou Yu, Robert A. Jones,  

E-Print Network [OSTI]

and as an integral element of biopolymeric organic light emitting diodes. We have shown [1] that these BioLEDs have

Steckl, Andrew J.

206

Understanding the role of ultra-thin polymeric interlayers in improving efficiency of polymer light emitting diodes  

SciTech Connect (OSTI)

Insertion of ultra-thin polymeric interlayers (ILs) between the poly(3,4-ethylenedioxythiophene):polystyrene sulphonate hole injection and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) light emission layers of polymer light emitting diodes (PLEDs) can significantly increase their efficiency. In this paper, we investigate experimentally a broad range of probable causes of this enhancement with an eye to determining which IL parameters have the most significant effects. The importance of hole injection and electron blocking was studied through varying the IL material (and consequently its electronic energy levels) for both PLED and hole-only diode structures. The role of IL conductivity was examined by introducing a varying level of charge-transfer doping through blending the IL materials with a strong electron-accepting small molecule in concentrations from 1% to 7% by weight. Depositing ILs with thicknesses below the exciton diffusion length of ?15?nm allowed the role of the IL as a physical barrier to exciton quenching to be probed. IL containing PLEDs was also fabricated with Lumation Green Series 1300 (LG 1300) light emission layers. On the other hand, the PLEDs were modeled using a 3D multi-particle Kinetic Monte Carlo simulation coupled with an optical model describing how light is extracted from the PLED. The model describes charge carrier transport and interactions between electrons, holes, singlets, and triplets, with the current density, luminance, and recombination zone (RZ) locations calculated for each PLED. The model shows F8BT PLEDs have a narrow charge RZ adjacent to the anode, while LG 1300 PLEDs have a wide charge RZ that is evenly distributed across the light emitting layer. Varying the light emitting layer from F8BT to Lumation Green Series 1300, we therefore experimentally examine the dependence of the IL function, specifically in regard to anode-side exciton quenching, on the location of the RZ. We found an exponential dependence of F8BT PLED luminance on the difference, ?, in the highest occupied to lowest unoccupied molecular orbital energy gap between the light emitting polymer and a semiconducting polymeric IL, with ? consequently the most important parameter determining efficiency. Understanding the exponential effect that wider energy gap IL materials have on exciton quenching may allow ? to be used to better guide PLED structure design.

Bailey, Jim; Wang, Xuhua; Bradley, Donal D. C.; Kim, Ji-Seon, E-mail: ji-seon.kim@imperial.ac.uk [Department of Physics and Centre for Plastic Electronics, South Kensington Campus, Imperial College London, London SW7 2AZ (United Kingdom); Wright, Edward N.; Walker, Alison B. [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom)

2014-05-28T23:59:59.000Z

207

Nanospherical-lens lithographical Ag nanodisk arrays embedded in p-GaN for localized surface plasmon-enhanced blue light emitting diodes  

SciTech Connect (OSTI)

Large-scale Ag nanodisks (NDs) arrays fabricated using nanospherical-lens lithography (NLL) are embedded in p-GaN layer of an InGaN/GaN light-emitting diode (LED) for generating localized surface plasmon (LSP) coupling with the radiating dipoles in the quantum-well (QWs). Based on the Ag NDs with the controlled surface coverage, LSP leads to the improved crystalline quality of regrowth p-GaN, increased photoluminescence (PL) intensity, reduced PL decay time, and enhanced output power of LED. Compared with the LED without Ag NDs, the optical output power at a current of 350 mA of the LSP-enhanced LEDs with Ag NDs having a distance of 20 and 35 nm to QWs is increased by 26.7% and 31.1%, respectively. The electrical characteristics and optical properties of LEDs with embedded Ag NPs are dependent on the distance of between Ag NPs and QWs region. The LED with Ag NDs array structure is also found to exhibit reduced emission divergence, compared to that without Ag NDs.

Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Wu, Kui; Sun, Bo; Zhang, Yonghui; Chen, Yu; Huo, Ziqiang; Hu, Qiang; Wang, Junxi; Zeng, Yiping; Li, Jinmin [State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 (China); Lan, Ding [National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100080 (China)

2014-06-15T23:59:59.000Z

208

Comparative study of field-dependent carrier dynamics and emission kinetics of InGaN/GaN light-emitting diodes grown on (11 2 2) semipolar versus (0001) polar  

E-Print Network [OSTI]

Articles you may be interested in Ultraviolet light-emitting diodes grown by plasma-assisted molecular beam light-emitting diodes prepared on ( 11 2 ¯ 2 ) -plane GaN J. Appl. Phys. 100, 113109 (2006); 10.1063/1.2382667 Demonstration of a semipolar ( 10 1 ¯ 3 ¯ ) In Ga N Ga N green light emitting diode Appl. Phys. Lett. 87, 231110

Demir, Hilmi Volkan

209

E-Print Network 3.0 - af led lyskilder Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Birgitte Thestrup... Roskilde, Denmark Abstract Research and development within Light Emitting Diode or LED Source: Ris National Laboratory Collection: Multidisciplinary...

210

The use of short-period InGaN/GaN superlattices in blue-region light-emitting diodes  

SciTech Connect (OSTI)

Optical and light-emitting diode structures with an active InGaN region containing short-period InGaN/GaN superlattices are studied. It is shown that short-period superlattices are thin two-dimensional layers with a relatively low In content that contain inclusions with a high In content 1-3 nm thick. Inclusions manifest themselves from the point of view of optical properties as a nonuniform array of quantum dots involved in a residual quantum well. The use of short-period superlattices in light-emitting diode structures allows one to decrease the concentration of nonradiative centers, as well as to increase the injection of carriers in the active region due to an increase in the effective height of the AlGaN barrier, which in general leads to an increase in the quantum efficiency of light-emitting diodes.

Sizov, V. S., E-mail: vsizov@mail.ioffe.ru; Tsatsulnikov, A. F.; Sakharov, A. V.; Lundin, W. V.; Zavarin, E. E.; Cherkashin, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Hytch, M. J. [National Center for Scientific Research (CNRS), Center for Material Elaboration and Structural Studies (CEMES) (France); Nikolaev, A. E. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Mintairov, A. M.; He Yan; Merz, J. L. [University of Notre Dame, EE Department (United States)

2010-07-15T23:59:59.000Z

211

Photonic crystal light emitting diode based on Er and Si nanoclusters co-doped slot waveguide  

SciTech Connect (OSTI)

We report on the design, fabrication, and electro-optical characterization of a light emitting device operating at 1.54??m, whose active layer consists of silicon oxide containing Er-doped Si nanoclusters. A photonic crystal (PhC) is fabricated on the top-electrode to enhance the light extraction in the vertical direction, and thus the external efficiency of the device. This occurs if a photonic mode of the PhC slab is resonant with the Er emission energy, as confirmed by theoretical calculations and experimental analyses. We measure an increase of the extraction efficiency by a factor of 3 with a high directionality of light emission in a narrow vertical cone. External quantum efficiency and power efficiency are among the highest reported for this kind of material. These results are important for the realization of CMOS-compatible efficient light emitters at telecom wavelengths.

Lo Savio, R.; Galli, M.; Liscidini, M.; Andreani, L. C. [Dipartimento di Fisica, Università di Pavia, Via Bassi 6, 27100 Pavia (Italy); Franzò, G.; Iacona, F.; Miritello, M. [MATIS-IMM CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Irrera, A. [CNR-IPCF, Viale Ferdinando Stagno d'Alcontres 37, 98158 Messina (Italy); Sanfilippo, D.; Piana, A. [ST Microelectronics, Stradale Primosole 50, 95121 Catania (Italy); Priolo, F. [MATIS-IMM CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Scuola Superiore di Catania, Università di Catania, Via Valdisavoia 9, 95123 Catania (Italy)

2014-03-24T23:59:59.000Z

212

TESLA-FEL 2007-03 Application of low cost GaAs LED as neutron  

E-Print Network [OSTI]

neutrons in unbiased Gallium Arsenide (GaAs) Light Emitting Diodes (LED) resulted in a reduction Keywords: COTS components, Displacement damage, Electron Linear Accelerator, GaAs Light emitting diode (LED) Gallium Arsenide (GaAs) light emitting diode (LED) for the assessment of integrated neutron fluence

213

Phosphor-free nanopyramid white light-emitting diodes grown on (101{sup ¯}1) planes using nanospherical-lens photolithography  

SciTech Connect (OSTI)

We reported a high-efficiency and low-cost nano-pattern method, the nanospherical-lens photolithography technique, to fabricate a SiO{sub 2} mask for selective area growth. By controlling the selective growth, we got a highly ordered hexagonal nanopyramid light emitting diodes with InGaN/GaN quantum wells grown on nanofacets, demonstrating an electrically driven phosphor-free white light emission. We found that both the quantum well width and indium incorporation increased linearly along the (101{sup ¯}1) planes towards the substrate and the perpendicular direction to the (101{sup ¯}1) planes as well. Such spatial distribution was responsible for the broadband emission. Moreover, using cathodoluminescence techniques, it was found that the blue emission originated from nanopyramid top, resembling the quantum dots, green emission from the InGaN quantum wells layer at the middle of sidewalls, and yellow emission mainly from the bottom of nanopyramid ridges, similar to the quantum wires.

Wu, Kui [State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China) [State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology/State Key Lab on Integrated Optoelectronics, Tsinghua University, Beijing 100084 (China); Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Wei, Xuecheng; Zheng, Haiyang; Chen, Yu; Lu, Hongxi; Wang, Junxi; Li, Jinmin [State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)] [State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Lan, Ding [National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China)] [National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Huang, Kai [Platform of Characterization and Test, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215000 (China)] [Platform of Characterization and Test, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215000 (China); Luo, Yi [Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology/State Key Lab on Integrated Optoelectronics, Tsinghua University, Beijing 100084 (China)] [Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology/State Key Lab on Integrated Optoelectronics, Tsinghua University, Beijing 100084 (China)

2013-12-09T23:59:59.000Z

214

Low-cost electrochemical treatment of indium tin oxide anodes for high-efficiency organic light-emitting diodes  

SciTech Connect (OSTI)

We demonstrate a simple low-cost approach as an alternative to conventional O{sub 2} plasma treatment to modify the surface of indium tin oxide (ITO) anodes for use in organic light-emitting diodes. ITO is functionalized with F{sup ?} ions by electrochemical treatment in dilute hydrofluoric acid. An electrode with a work function of 5.2?eV is achieved following fluorination. Using this electrode, a maximum external quantum efficiency of 26.0% (91?cd/A, 102?lm/W) is obtained, which is 12% higher than that of a device using the O{sub 2} plasma-treated ITO. Fluorination also increases the transparency in the near-infrared region.

Hui Cheng, Chuan, E-mail: chengchuanhui@dlut.edu.cn; Shan Liang, Ze; Gang Wang, Li; Dong Gao, Guo; Zhou, Ting; Ming Bian, Ji; Min Luo, Ying [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Tong Du, Guo, E-mail: dugt@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2014-01-27T23:59:59.000Z

215

Barrier performance optimization of atomic layer deposited diffusion barriers for organic light emitting diodes using x-ray reflectivity investigations  

SciTech Connect (OSTI)

The importance of O{sub 3} pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al{sub 2}O{sub 3} layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O{sub 3} pulse durations longer than 15?s produce dense and thin Al{sub 2}O{sub 3} layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes.

Singh, Aarti, E-mail: aarti.singh@namlab.com; Schröder, Uwe [Nanoelectronics Materials Laboratory NaMLab gGmbH, Nöthnitzer Str. 64, 01187 Dresden (Germany)] [Nanoelectronics Materials Laboratory NaMLab gGmbH, Nöthnitzer Str. 64, 01187 Dresden (Germany); Klumbies, Hannes; Müller-Meskamp, Lars; Leo, Karl [Dresden Innovation Center Energy Efficiency, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany)] [Dresden Innovation Center Energy Efficiency, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Geidel, Marion; Knaut, Martin; Hoßbach, Christoph; Albert, Matthias [Institute of Semiconductor and Microsystems Technology, Technische Universität Dresden, 01187 Dresden (Germany)] [Institute of Semiconductor and Microsystems Technology, Technische Universität Dresden, 01187 Dresden (Germany); Mikolajick, Thomas [Nanoelectronics Materials Laboratory NaMLab gGmbH, Nöthnitzer Str. 64, 01187 Dresden (Germany) [Nanoelectronics Materials Laboratory NaMLab gGmbH, Nöthnitzer Str. 64, 01187 Dresden (Germany); Institute of Semiconductor and Microsystems Technology, Technische Universität Dresden, 01187 Dresden (Germany)

2013-12-02T23:59:59.000Z

216

Enhancing the quantum efficiency of InGaN yellow-green light-emitting diodes by growth interruption  

SciTech Connect (OSTI)

We studied the effect of multiple interruptions during the quantum well growth on emission-efficiency enhancement of InGaN-based yellow-green light emitting diodes on c-plane sapphire substrate. The output power and dominant wavelength at 20?mA are 0.24 mW and 556.3?nm. High resolution x-ray diffraction, photoluminescence, and electroluminescence measurements demonstrate that efficiency enhancement could be partially attributed to crystal quality improvement of the active region resulted from reduced In clusters and relevant defects on the surface of InGaN layer by introducing interruptions. The less tilted energy band in the quantum well is also caused by the decrease of In-content gradient along c-axis resulted from In segregation during the interruptions, which increases spatial overlap of electron-hole wavefunction and thus the internal quantum efficiency. The latter also leads to smaller blueshift of dominant wavelength with current increasing.

Du, Chunhua; Ma, Ziguang; Zhou, Junming; Lu, Taiping; Jiang, Yang; Zuo, Peng; Jia, Haiqiang; Chen, Hong, E-mail: hchen@iphy.ac.cn [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-08-18T23:59:59.000Z

217

Carrier recombination mechanisms and efficiency droop in GaInN/GaN light-emitting diodes  

SciTech Connect (OSTI)

We model the carrier recombination mechanisms in GaInN/GaN light-emitting diodes as R=An+Bn{sup 2} +Cn{sup 3} +f(n) , where f(n) represents carrier leakage out of the active region. The term f(n) is expanded into a power series and shown to have higher-than-third-order contributions to the recombination. The total third-order nonradiative coefficient (which may include an f(n) leakage contribution and an Auger contribution) is found to be 8×10{sup ?29} ?cm{sup 6} ?s{sup ?1} . Comparison of the theoretical ABC+f(n) model with experimental data shows that a good fit requires the inclusion of the f(n) term.

Dai, Qi; Shan, Qifeng; Wang, Jing; Chhajed, Sameer; Cho, Jaehee; Schubert, E. Fred; Crawford, Mary H.; Koleske, Daniel D.; Kim, Min-Ho; Park, Yongjo

2010-01-01T23:59:59.000Z

218

Monolithic phosphor-free InGaN/GaN quantum dot wavelength converter white light emitting diodes  

SciTech Connect (OSTI)

We report the characteristics of phosphor-free self-organized InGaN/GaN quantum dot wavelength converter white light emitting diodes grown by plasma assisted molecular beam epitaxy. The exciting quantum dots, in which electrically injected carriers recombine, are blue-emitting and the converter dots are red-emitting. We have studied the effect of tuning the number of dot layers and the peak emission wavelength of the exciting and converter dots on the nature of the emitted white light, in terms of the chromaticity coordinates and correlated color temperature. Depending on the values of these wavelengths, color temperatures in the range of 4420–6700?K have been derived at a current density of 45?A/cm{sup 2} across multiple devices. The variation of the color temperature with change in injection current is found to be very small.

Jahangir, Shafat; Bhattacharya, Pallab, E-mail: pkb@eecs.umich.edu [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States); Pietzonka, Ines; Strassburg, Martin [OSRAM Opto Semiconductors GmbH, Leibnizstrasse 4, Regensburg (Germany)

2014-09-15T23:59:59.000Z

219

Enhanced light emission from top-emitting organic light-emitting diodes by optimizing surface plasmon polariton losses  

E-Print Network [OSTI]

We demonstrate enhanced light extraction for monochrome top-emitting organic light-emitting diodes (OLEDs). The enhancement by a factor of 1.2 compared to a reference sample is caused by the use of a hole transport layer (HTL) material possessing a low refractive index (1.52). The low refractive index reduces the in-plane wave vector of the surface plasmon polariton (SPP) excited at the interface between the bottom opaque metallic electrode (anode) and the HTL. The shift of the SPP dispersion relation decreases the power dissipated into lost evanescent excitations and thus increases the outcoupling efficiency, although the SPP remains constant in intensity. The proposed method is suitable for emitter materials owning isotropic orientation of the transition dipole moments as well as anisotropic, preferentially horizontal orientation, resulting in comparable enhancement factors. Furthermore, for sufficiently low refractive indices of the HTL material, the SPP can be modeled as a propagating plane wave within ot...

Fuchs, Cornelius; Wieczorek, Martin; Gather, Malte C; Hofmann, Simone; Reineke, Sebastian; Leo, Karl; Scholz, Reinhard

2015-01-01T23:59:59.000Z

220

Highly efficient inverted top emitting organic light emitting diodes using a transparent top electrode with color stability on viewing angle  

SciTech Connect (OSTI)

We report a highly efficient phosphorescent green inverted top emitting organic light emitting diode with excellent color stability by using the 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile/indium zinc oxide top electrode and bis(2-phenylpyridine)iridium(III) acetylacetonate as the emitter in an exciplex forming co-host system. The device shows a high external quantum efficiency of 23.4% at 1000?cd/m{sup 2} corresponding to a current efficiency of 110?cd/A, low efficiency roll-off with 21% at 10?000?cd/m{sup 2} and low turn on voltage of 2.4?V. Especially, the device showed very small color change with the variation of ?x?=?0.02, ?y?=?0.02 in the CIE 1931 coordinates as the viewing angle changes from 0° to 60°. The performance of the device is superior to that of the metal/metal cavity structured device.

Kim, Jung-Bum; Lee, Jeong-Hwan; Moon, Chang-Ki; Kim, Jang-Joo, E-mail: jjkim@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

2014-02-17T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

ZnO light-emitting diode grown by plasma-assisted metal organic chemical vapor deposition  

SciTech Connect (OSTI)

We report a breakthrough in fabricating ZnO homojunction light-emitting diode by metal organic chemical vapor deposition. Using NO plasma, we are able to grow p-type ZnO thin films on n-type bulk ZnO substrates. The as-grown films on glass substrates show hole concentration of 10{sup 16}-10{sup 17} cm{sup -3} and mobility of 1-10 cm{sup 2} V{sup -1} s{sup -1}. Room-temperature photoluminescence spectra reveal nitrogen-related emissions. A typical ZnO homojunction shows rectifying behavior with a turn-on voltage of about 2.3 V. Electroluminescence at room temperature has been demonstrated with band-to-band emission at I=40 mA and defect-related emissions in the blue-yellow spectrum range.

Xu, W.Z.; Ye, Z.Z.; Zeng, Y.J.; Zhu, L.P.; Zhao, B.H.; Jiang, L.; Lu, J.G.; He, H.P.; Zhang, S.B. [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

2006-04-24T23:59:59.000Z

222

Voltage-induced electroluminescence characteristics of hybrid light-emitting diodes with CdSe/Cd/ZnS core-shell nanoparticles embedded in a conducting polymer on plastic substrates  

SciTech Connect (OSTI)

We investigate the electroluminescence (EL) characteristics of a hybrid light-emitting diode (HyLED) with an emissive layer comprised of CdSe/Cd/ZnS core-shell nanoparticles (NPs) embedded in poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) on a plastic substrate. The EL characteristics change dramatically with increasing of the biased voltage. At low voltages, recombination of electrons and holes occurs only in the PFO film because of poor charge transfer in the PFO-CdSe/Cd/ZnS NPs composite film, while the color of the light-emitting from the HyLED changes from blue to red as the biased voltage increases from 7.5 to 17.5?V. We examine and discuss the mechanism of this color tunability.

Kwak, Kiyeol; Cho, Kyoungah, E-mail: chochem@korea.ac.kr, E-mail: sangsig@korea.ac.kr; Kim, Sangsig, E-mail: chochem@korea.ac.kr, E-mail: sangsig@korea.ac.kr [Department of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)] [Department of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2014-03-10T23:59:59.000Z

223

Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography  

SciTech Connect (OSTI)

The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCs is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350?mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.

Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin [Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2014-07-07T23:59:59.000Z

224

Light extraction enhanced white light-emitting diodes with multi-layered phosphor configuration  

E-Print Network [OSTI]

The phosphor conversion efficiency ( ? PCE ) can becalculated by ? PCE = ? q × ? p = P Y + P R P B o ? P Bconversion efficiency (PCE) of BL-R/Y LEDs and mixed-RY LEDs

You, Jiun Pyng; Tran, Nguyen T.; Shi, Frank G.

2010-01-01T23:59:59.000Z

225

Remarkably reduced efficiency droop by using staircase thin InGaN quantum barriers in InGaN based blue light emitting diodes  

SciTech Connect (OSTI)

The efficiency droop of InGaN/GaN(InGaN) multiple quantum well (MQW) light emitting diodes (LEDs) with thin quantum barriers (QB) is studied. With thin GaN QB (3?nm–6?nm thickness), the efficiency droop is not improved, which indicates that hole transport cannot be significantly enhanced by the thin GaN QBs. On the contrary, the efficiency droop was remarkably reduced by using a InGaN staircase QB (InGaN SC-QB) MQWs structure where InGaN SC-QBs lower the transport energy barrier of holes. The efficiency droop ratio was as low as 3.3% up to 200?A/cm{sup 2} for the InGaN SC-QB LED. By using monitoring QW with longer wavelength we observe a much uniform carrier distribution in the InGaN SC-QB LEDs, which reveals the mechanism of improvement in the efficiency droop.

Zhou, Kun; Ikeda, Masao, E-mail: mikeda2013@sinano.ac.cn, E-mail: jpliu2010@sinano.ac.cn; Liu, Jianping, E-mail: mikeda2013@sinano.ac.cn, E-mail: jpliu2010@sinano.ac.cn; Zhang, Shuming; Li, Deyao; Zhang, Liqun; Yang, Hui [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Sciences, Suzhou (China); Cai, Jin; Wang, Hui; Wang, H. B. [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Sciences, Suzhou (China); Suzhou Nanojoin Photonics Co., Ltd., Suzhou (China)

2014-10-27T23:59:59.000Z

226

GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al{sub 2}O{sub 3} powder  

SciTech Connect (OSTI)

Surface-textured InGaN/GaN light-emitting diodes (LEDs) coated with transparent Al{sub 2}O{sub 3} powder were fabricated by natural lithography combined with inductively coupled plasma etching. For surface texturing, 300 nm size Al{sub 2}O{sub 3} powder is used as an etching mask by simply coating the surface using a spin-coating process. Also, the powders are left on the surface after surface texturing to further increase extraction efficiency. At 20 mA, the light output power of the textured indium tin oxide (ITO) InGaN/GaN LEDs coated with the Al{sub 2}O{sub 3} powder is enhanced by {approx}112% compared with the conventional nontextured ITO LED. The enhanced light output power is attributed to the improved extraction efficiency resulting from an overall decrease in the total internal reflection due to the textured surface and the Al{sub 2}O{sub 3} powder coating.

Kim, T. K.; Kim, S. H.; Yang, S. S.; Son, J. K.; Lee, K. H.; Hong, Y. G.; Shim, K. H.; Yang, J. W.; Lim, K. Y.; Yang, G. M. [Department of Semiconductor and Chemical Engineering and Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Bae, S. J. [Optowell Co., Ltd., 308, Semiconductor Physics Research Center, 664-14, Dukjin-Dong, Dukjin-Gu, Jeonju 561-756 (Korea, Republic of)

2009-04-20T23:59:59.000Z

227

The impact of trench defects in InGaN/GaN light emitting diodes and implications for the “green gap” problem  

SciTech Connect (OSTI)

The impact of trench defects in blue InGaN/GaN light emitting diodes (LEDs) has been investigated. Two mechanisms responsible for the structural degradation of the multiple quantum well (MQW) active region were identified. It was found that during the growth of the p-type GaN capping layer, loss of part of the active region enclosed within a trench defect occurred, affecting the top-most QWs in the MQW stack. Indium platelets and voids were also found to form preferentially at the bottom of the MQW stack. The presence of high densities of trench defects in the LEDs was found to relate to a significant reduction in photoluminescence and electroluminescence emission efficiency, for a range of excitation power densities and drive currents. This reduction in emission efficiency was attributed to an increase in the density of non-radiative recombination centres within the MQW stack, believed to be associated with the stacking mismatch boundaries which form part of the sub-surface structure of the trench defects. Investigation of the surface of green-emitting QW structures found a two decade increase in the density of trench defects, compared to its blue-emitting counterpart, suggesting that the efficiency of green-emitting LEDs may be strongly affected by the presence of these defects. Our results are therefore consistent with a model that the “green gap” problem might relate to localized strain relaxation occurring through defects.

Massabuau, F. C.-P., E-mail: fm350@cam.ac.uk; Oehler, F.; Pamenter, S. K.; Thrush, E. J.; Kappers, M. J.; Humphreys, C. J.; Oliver, R. A. [Department of Materials Science and Metallurgy, University of Cambridge, 22 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Davies, M. J.; Dawson, P. [Photon Science Institute, School of Physics and Astronomy, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom); Kovács, A.; Dunin-Borkowski, R. E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt- Straße, D-52425 Jülich (Germany); Williams, T.; Etheridge, J. [Monash Centre for Electron Microscopy, Monash University, Clayton Campus, VIC 3800 (Australia); Hopkins, M. A.; Allsopp, D. W. E. [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom)

2014-09-15T23:59:59.000Z

228

Comparison of the properties of AlGaInN light-emitting diode chips of vertical and flip-chip design using silicon as the a submount  

SciTech Connect (OSTI)

Vertical and flip-chip light-emitting diode (LED) chips are compared from the viewpoint of the behavior of current spreading in the active region and the distribution of local temperatures and thermal resistances of chips. AlGaInN LED chips of vertical design are fabricated using Si as a submount and LED flipchips were fabricated with the removal of a sapphire substrate. The latter are also mounted on a Si submount. The active regions of both chips are identical and are about 1 mm{sup 2} in size. It is shown that both the emittance of the crystal surface in the visible range and the distribution of local temperatures estimated from radiation in the infrared region are more uniform in crystals of vertical design. Heat removal from flip-chips is insufficient in regions of the n contact, which do not possess good thermal contact with the submount. As a result, the total thermal resistances between the p-n junction and the submount both for the vertical chips and for flip-chips are approximately 1 K/W. The total area of the flip-chips exceeds that of the vertical design chips by a factor of 1.4.

Markov, L. K., E-mail: l.markov@mail.ioffe.ru; Smirnova, I. P.; Pavlyuchenko, A. S. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Kukushkin, M. V.; Vasil'eva, E. D. [ZAO Innovation 'Tetis' (Russian Federation); Chernyakov, A. E. [Russian Academy of Sciences, Science-and-Technology Microelectronics Center (Russian Federation); Usikov, A. S. [De Core Nanosemiconductors Ltd. (India)

2013-03-15T23:59:59.000Z

229

E-Print Network 3.0 - alingap light emitting Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: :http:www.eee.hku.hkgpang Abstract The visible light from an LED (light emitting diode) traffic light can be modulated and encoded... on the description of an audio...

230

Layering Mismatched Lattices Creates Long-Sought-After Green Light-Emitting Diode (Fact Sheet)  

SciTech Connect (OSTI)

Scientists at the National Renewable Energy Laboratory (NREL) invent a deep green LED that can lead to higher-efficiency white light, lower electric bills.

Not Available

2011-02-01T23:59:59.000Z

231

Enhancement of Radiative Efficiency with Staggered InGaN Quantum Well Light Emitting Diodes  

SciTech Connect (OSTI)

The technology on the large overlap InGaN QWs developed in this program is currently implemented in commercial technology in enhancing the internal quantum efficiency in major LED industry in US and Asia. The scientific finding from this work supported by the DOE enabled the implementation of this step-like staggered quantum well in the commercial LEDs.

Tansu, Nelson; Dierolf, Volkmar; Huang, Gensheng; Penn, Samson; Zhao, Hongping; Liu, Guangyu; Li, Xiaohang; Poplawsky, Jonathan

2011-07-14T23:59:59.000Z

232

Confocal microphotoluminescence of InGaN-based light-emitting diodes Koichi Okamoto,a  

E-Print Network [OSTI]

for conventional incandescent and fluorescent light bulbs.5 However, luminous efficacies of commercial white LEDs spectrum region, the external quantum efficiency ext of the LED has achieved 20% at room temperature 25 lm/W have been still lower than that of fluorescent tubes 75 lm/W . Thus, the most important re

Okamoto, Koichi

233

Illuminating Solar Decathlon Homes: Exploring Next Generation Lighting Technology - Light Emitting Diodes  

SciTech Connect (OSTI)

This report was prepared by PNNL for the US Department of Energy Building Technologies Program, Solid-State Lighting Program. The report will be provided to teams of university students who are building houses for the 2009 Solar Decathlon, a home design competition sponsored in part by DOE, to encourage teams to build totally solar powered homes. One aspect of the competition is lighting. This report provides the teams with information about LED lighting that can help them determine how they incorporate LED lighting into their homes. The report provides an overview of LED technology, a status of where LED technology is today, questions and answers about lighting quality, efficiency, lifetime etc.; numerous examples of LED products; and several weblinks for further research.

Gordon, Kelly L.; Gilbride, Theresa L.

2008-05-22T23:59:59.000Z

234

Colloidal quantum-dot light-emitting diodes with metal-oxide charge  

E-Print Network [OSTI]

across the pixel area, and fabrication required the specialized deposition technique of energy-neutral over previously reported structures8,10 . Previous efforts at building colloidal quantum-dot (QD) LEDs concentrations and energy-band

235

An intentionally positioned (In,Ga)As quantum dot in a micron sized light emitting diode  

SciTech Connect (OSTI)

We have integrated individual (In,Ga)As quantum dots (QDs) using site-controlled molecular beam epitaxial growth into the intrinsic region of a p-i-n junction diode. This is achieved using an in situ combination of focused ion beam prepatterning, annealing, and overgrowth, resulting in arrays of individually electrically addressable (In,Ga)As QDs with full control on the lateral position. Using microelectroluminescence spectroscopy we demonstrate that these QDs have the same optical quality as optically pumped Stranski-Krastanov QDs with random nucleation located in proximity to a doped interface. The results suggest that this technique is scalable and highly interesting for different applications in quantum devices.

Mehta, M.; Michaelis de Vasconcellos, S.; Zrenner, A.; Meier, C. [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), University of Paderborn, Warburger Street 100, 33098 Paderborn (Germany); Reuter, D.; Wieck, A. D. [Applied Solid State Physics, Ruhr-University of Bochum, Universitaetsstr. 150, 44780 Bochum (Germany)

2010-10-04T23:59:59.000Z

236

The Spectrum of Clean Energy Innovationinnovati nGreen Light-Emitting Diode Makes  

E-Print Network [OSTI]

- ing as an efficient solid-state light source, able to replace incandescent and compact fluorescent light bulbs in many applications. A new green LED from NREL may yield more efficient solid to accelerating market deployment, NREL works in partnership with private industry to drive the transformation

237

Indium-tin-oxide-free tris(8-hydroxyquinoline) Al organic light-emitting diodes with 80% enhanced power efficiency  

SciTech Connect (OSTI)

Efficient indium tin oxide (ITO)-free small molecule organic light-emitting diodes (SMOLEDs) with multilayered highly conductive poly(3,4-ethylenedioxy thiophene):poly(styrenesulfonate) (PEDOT:PSS) as the anode are demonstrated. PEDOT:PSS/MoO{sub 3}/N,N'-diphenyl- N,N'-bis(1-naphthylphenyl)-1,1'-biphenyl-4,4'-diamine (NPD)/tris(8-hydroxyquinoline) Al (Alq{sub 3})/4,7-diphenyl-1,10-phenanthroline (BPhen)/LiF/Al SMOLEDs exhibited a peak power efficiency of 3.82 lm/W, 81% higher than that of similar ITO-based SMOLEDs (2.11 lm/W). The improved performance is believed to be due to the higher work function, lower refractive index, and decreased surface roughness of PEDOT:PSS vs ITO, and to Ohmic hole injection from PEDOT:PSS to the NPD layer via the MoO{sub 3} interlayer. The results demonstrate that PEDOT:PSS can substitute ITO in SMOLEDs with strongly improved device performance.

Cai, Min; Xiao, Teng; Liu, Rui; Chen, Ying; Shinar, Ruth; Shinar, Joseph

2011-10-11T23:59:59.000Z

238

Role of chemical reactions of arylamine hole transport materials in operational degradation of organic light-emitting diodes  

SciTech Connect (OSTI)

We report that the representative arylamine hole transport materials undergo chemical transformations in operating organic light-emitting diode (OLED) devices. Although the underlying chemical mechanisms are too complex to be completely elucidated, structures of several identified degradation products point at dissociations of relatively weak carbon-nitrogen and carbon-carbon bonds in arylamine molecules as the initiating step. Considering the photochemical reactivities, the bond dissociation reactions of arylamines occur by the homolysis of the lowest singlet excited states formed by recombining charge carriers in the operating OLED device. The subsequent chemical reactions are likely to yield long-lived, stabilized free radicals capable of acting as deep traps--nonradiative recombination centers and fluorescence quenchers. Their presence in the hole transport layer results in irreversible hole trapping and manifests as a positive fixed charge. The extent and localization of chemical transformations in several exemplary devices suggest that the free radical reactions of hole transporting materials, arylamines, can be sufficient to account for the observed luminance efficiency loss and voltage rise in operating OLEDs. The relative bond strengths and excited state energies of OLED materials appear to have a determining effect on the operational stability of OLED devices.

Kondakov, Denis Y. [Eastman Kodak Company, Rochester, New York 14650-2103 (United States)

2008-10-15T23:59:59.000Z

239

Highly-selective wettability on organic light-emitting-diodes patterns by sequential low-power plasmas  

SciTech Connect (OSTI)

Patterned organic light-emitting-diode substrates were treated by oxygen (O{sub 2}) and tetrafluoromethane (CF{sub 4}) radio-frequency (rf, 13.56 MHz) plasmas of low-power (close to 1 W) that were capacitively-coupled. An unexpected wettability contrast (water contact angle difference up to 90 deg. ) between the indium-tin-oxide anode and the bank resist regions was achieved, providing excellent conditioning prior to the ink-jet printing. This selectivity was found to be adjustable by varying the relative exposure time to the O{sub 2} and CF{sub 4} sequential plasmas. Static contact angle measurements and extensive x-ray photoelectron spectroscopy analyses showed that the wetting properties depend on the carbon and fluorine chemical functional groups formed at the outermost surface layers, whereas atomic force microscopy images did not show a morphological change. Plasma optical emission spectroscopy and ion mass spectroscopy suggested that surface functionalization was initiated by energy transfer from ionic species (O{sup +}, O{sub 2}{sup +}, CF{sup +}, CF{sub 2}{sup +}, and CF{sub 3}{sup +}) and excited neutrals (O{sup *} and F{sup *}). The absolute ion fluxes measured on the substrates were up to 10{sup 14} cm{sup -2} s{sup -1} and the ion energies up to 20 eV, despite the low powers applied during the process.

Svarnas, P.; Edwards, A. J.; Bradley, J. W. [Department of Electrical Engineering and Electronics, Technological Plasmas Group, University of Liverpool, Merseyside L69 3GJ (United Kingdom); Yang, L.; Munz, M.; Shard, A. G. [Analytical Science Division, National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)

2010-05-15T23:59:59.000Z

240

LED Traffic Light as a Communications Device Grantham Pang, Thomas Kwan, Chi-Ho Chan, Hugh Liu.  

E-Print Network [OSTI]

:http://www.eee.hku.hk/~gpang Abstract The visible light from an LED (light emitting diode) traffic light can be modulated and encoded on the description of an audio information system made up of high brightness, visible light emitting diodes (LEDs messages 1. Introduction Recently, high intensity light emitting diodes for traffic signals are available

Pang, Grantham

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Investigation on Operating Characteristics of RGB LEDs.  

E-Print Network [OSTI]

??This thesis seeks to gain a better understanding on operating characteristics of the three primary color light emitting diode (LED). By applying direct, pulse and… (more)

Liao, Chi-nan

2007-01-01T23:59:59.000Z

242

Efficient Driver for Dimmable White LED Lighting.  

E-Print Network [OSTI]

??A high efficiency driver circuit is proposed for Light Emitting Diode (LED) lamps with dimming feature. The current regulation is accomplished by processing partial power… (more)

Yang, Wen-ching

2011-01-01T23:59:59.000Z

243

Recipient luminophoric mediums having narrow spectrum luminescent materials and related semiconductor light emitting devices and methods  

DOE Patents [OSTI]

Light emitting devices include a light emitting diode ("LED") and a recipient luminophoric medium that is configured to down-convert at least some of the light emitted by the LED. In some embodiments, the recipient luminophoric medium includes a first broad-spectrum luminescent material and a narrow-spectrum luminescent material. The broad-spectrum luminescent material may down-convert radiation emitted by the LED to radiation having a peak wavelength in the red color range. The narrow-spectrum luminescent material may also down-convert radiation emitted by the LED into the cyan, green or red color range.

LeToquin, Ronan P; Tong, Tao; Glass, Robert C

2014-12-30T23:59:59.000Z

244

Optical remote monitoring of CH/sub 4/ gas using low-loss optical fiber link and InGaAsP light-emitting diode in 1. 33-. mu. m region  

SciTech Connect (OSTI)

Purely optical remote monitoring of low-level CH/sub 4/ gas is realized for the first time by the method employing a 2-km long-distance, low-loss silica optical fiber link and a compact absorption cell in conjunction with a high radiant InGaAsP light-emitting diode (LED) at 1.33 ..mu..m. Based on the present experiment, the detection limit of CH/sub 4/ in air was confirmed to be approximately 2000 ppm, i.e., 4% of the lower explosion limit of CH/sub 4/. This result supports the conclusion that the fully optical remote sensing system incorporating ultralow loss optical fiber networks and near infrared LEDs or laser diodes can be extensively used for the detection and surveillance of various inflammable and/or explosive gases in industrial and mining complexes as well as in residential areas.

Chan, K.; Ito, H.; Inaba, H.

1983-10-01T23:59:59.000Z

245

Edge electroluminescence of the effective silicon point-junction light-emitting diode in the temperature range 80-300 K  

SciTech Connect (OSTI)

The edge electroluminescence spectra of silicon point-junction light-emitting diodes with a p-n junction area of 0.008 mm{sup 2} are studied at temperatures ranging from 80 to 300 K. Unprecedentedly high stability of the position of the spectral peak is observed at temperatures in the range between 130 and 300 K. The spectral characteristics of the light emitting diodes are studied at 80 K at different current densities up to 25 kA/cm{sup 2}. In contrast to the earlier reported data obtained at 300 K, the data obtained at 80 K do not show any noticeable Augerrecombination-related decrease in the quantum efficiency. From an analysis of the electroluminescence spectra at 80 K in a wide range of currents, it follows that radiative annihilation of free excitons is not a governing mechanism of electroluminescence in the entire emitting region in the base of the point-junction light-emitting diode at all currents used in the experiment.

Emel'yanov, A. M. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: Emelyanov@mail.ioffe.ru

2008-11-15T23:59:59.000Z

246

Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes  

SciTech Connect (OSTI)

We investigate the properties of N,N?-[(Diphenyl-N,N?-bis)9,9,-dimethyl-fluoren-2-yl]-benzidine (BF-DPB) as hole transport material (HTL) in organic light-emitting diodes (OLEDs) and compare BF-DPB to the commonly used HTLs N,N,N?,N?-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD), 2,2?,7,7?-tetrakis(N,N?-di-p-methylphenylamino)-9,9?-spirobifluorene (Spiro-TTB), and N,N?-di(naphtalene-1-yl)-N,N?-diphenylbenzidine (NPB). The influence of 2,2?-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ p-dopant) concentration in BF-DPB on the operation voltage and efficiency of red and green phosphorescent OLEDs is studied; best results are achieved at 4?wt. % doping. Without any light extraction structure, BF-DPB based red (green) OLEDs achieve a luminous efficacy of 35?.1?lm/W (74?.0?lm/W) at 1000?cd/m{sup 2} and reach a very high brightness of 10?000 cd/m{sup 2} at a very low voltage of 3.2 V (3.1 V). We attribute this exceptionally low driving voltage to the high ionization potential of BF-DPB which enables more efficient hole injection from BF-DPB to the adjacent electron blocking layer. The high efficiency and low driving voltage lead to a significantly lower luminous efficacy roll-off compared to the other compounds and render BF-DPB an excellent HTL material for highly efficient OLEDs.

Murawski, Caroline, E-mail: caroline.murawski@iapp.de; Fuchs, Cornelius; Hofmann, Simone; Leo, Karl [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01062 Dresden (Germany); Gather, Malte C. [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01062 Dresden (Germany); SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS Scotland (United Kingdom)

2014-09-15T23:59:59.000Z

247

Pousset, Obein, Razet, LED lighting quality with CQS samples CIE 2010 : Lighting Quality and Energy Efficiency, 14-17 March 2010, Vienna, Austria 1  

E-Print Network [OSTI]

A psychophysical experiment developed to evaluate light quality of Light Emitting Diodes (LEDs) is described. Keywords: Light Emitting Diode, quality of light, Color Rendering Index, Color Quality Scale, visual

Paris-Sud XI, Université de

248

Ruofan Wu, Hieu Pham Trung Nguyen and Zetian Mi INTRODUCTION TO LEDs  

E-Print Network [OSTI]

-in-a-Wire Light Emitting Diodes and Prevention Method Nano-electronic Devices and Materials, Electrical Computer., Efficiency droop in nitride-based light-emitting diodes. Physica Status Solidi a-Applications and Materials history. Nature Photonics 2007, 1 (4), 189-192. [4] Holonyak, N., Is the light emitting diode (LED

Barthelat, Francois

249

Coupled optical and electronic simulations of electrically pumped photonic-crystal-based LEDs  

E-Print Network [OSTI]

to investigate design tradeoffs in electrically pumped photonic crystal light emitting diodes. A finite. Keywords: Photonic crystal light emitting diode, electrically pumped device 1. INTRODUCTION Recently optoelectronic devices, such as light emitting diodes (LEDs) and lasers. It has been suggested that a thin slab

Dutton, Robert W.

250

LIGHT EMITTING DIODE  

E-Print Network [OSTI]

NOTES: 1. Dimensions for all drawings are in inches (mm). 2. Tolerance of ±.010 (.25) on all non-nominal dimensions unless otherwise specified.

High Output Power

251

GaInN light-emitting diodes using separate epitaxial growth for the p-type region to attain polarization-inverted electron-blocking layer, reduced electron leakage, and improved hole injection  

SciTech Connect (OSTI)

A GaInN light-emitting diode (LED) structure is analyzed that employs a separate epitaxial growth for the p-type region, i.e., the AlGaN electron-blocking layer (EBL) and p-type GaN cladding layer, followed by wafer or chip bonding. Such LED structure has a polarization-inverted EBL and allows for uncompromised epitaxial-growth optimization of the p-type region, i.e., without the need to consider degradation of the quantum-well active region during p-type region growth. Simulations show that such an LED structure reduces electron leakage, reduces the efficiency droop, improves hole injection, and has the potential to extend high efficiencies into the green spectral region.

Meyaard, David S., E-mail: meyaad@rpi.edu; Lin, Guan-Bo; Ma, Ming; Fred Schubert, E. [Future Chips Constellation, Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Future Chips Constellation, Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Cho, Jaehee [Future Chips Constellation, Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Future Chips Constellation, Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Semiconductor Physics Research Center, School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Han, Sang-Heon; Kim, Min-Ho; Shim, HyunWook; Sun Kim, Young [LED Business, Samsung Electronics, Yongin 446-920 (Korea, Republic of)] [LED Business, Samsung Electronics, Yongin 446-920 (Korea, Republic of)

2013-11-11T23:59:59.000Z

252

LED- ja loisteputkivalon vaikutus maitotaloustuotteiden ja perunan laatuun.  

E-Print Network [OSTI]

??Tutkielman kirjallisuuskatsauksessa tarkasteltiin valoa, erilaisia valonlähteitä ja niiden ominaisuuksia. Erityisesti keskityttiin LED (Light Emitting Diode) valoon ja sen ominaisuuksiin, koska sen käyttö myös yleisessä valaistuksessa… (more)

Solala, Kari

2009-01-01T23:59:59.000Z

253

Driver Circuit for White LED Lamps with TRIAC Dimming Control.  

E-Print Network [OSTI]

??An efficient Light Emitting Diode (LED) lamp driver circuit is proposed for retrofitting the conventionally used incandescent lamps with existing TRIAC dimmer. The dimming feature… (more)

Weng, Szu-Jung

2012-01-01T23:59:59.000Z

254

LED Provides Effective and Efficient Parking Area Lighting at...  

Broader source: Energy.gov (indexed) [DOE]

White Light Options for Parking Area Lighting Demonstration Assessment of Light Emitting Diode (LED) Street Lighting, Final Report Guide to FEMP-Designated Parking Lot...

255

Effects of Mg-doped AlN/AlGaN superlattices on properties of p-GaN contact layer and performance of deep ultraviolet light emitting diodes  

SciTech Connect (OSTI)

Mg-doped AlN/AlGaN superlattice (Mg-SL) and Mg-doped AlGaN epilayers have been investigated in the 284 nm deep ultraviolet (DUV) light emitting diodes (LEDs) as electron blocking layers. It was found that the use of Mg-SL improved the material quality of the p-GaN contact layer, as evidenced in the decreased density of surface pits and improved surface morphology and crystalline quality. The performance of the DUV LEDs fabricated using Mg-SL was significantly improved, as manifested by enhanced light intensity and output power, and reduced turn-on voltage. The improved performance is attributed to the enhanced blocking of electron overflow, and enhanced hole injection.

Al tahtamouni, T. M., E-mail: talal@yu.edu.jo [Department of Physics, Yarmouk University, Irbid 21163 (Jordan); Lin, J. Y.; Jiang, H. X. [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)] [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-04-15T23:59:59.000Z

256

An Brief Overview Of Using LEDs In Lab  

E-Print Network [OSTI]

Diodes · A Light-Emitting Diode (LED) is a special type of diode that emits photons (light) when current ­ Forward biased Diode Operation 0 V 5 V Current ~0 high (too high)5 V 0 V I anode cathode #12;3 Light-Emitting

Baas, Bevan

257

Space charge spectroscopy of integrated quantum well infrared photodetectorlight emitting diode  

E-Print Network [OSTI]

Space charge spectroscopy of integrated quantum well infrared photodetector±light emitting diode M ± light emitting diode (QWIP-LED). Quasistatic capacitance±voltage (C±V ) characteristics under reverse.V. All rights reserved. Keywords: Quantum-well infrared photodetector; Light-emitting diode; Space charge

Perera, A. G. Unil

258

Active region based on graded-gap InGaN/GaN superlattices for high-power 440- to 470-nm light-emitting diodes  

SciTech Connect (OSTI)

The structural and optical properties of light-emitting diode structures with an active region based on ultrathin InGaN quantum wells limited by short-period InGaN/GaN superlattices from both sides have been investigated. The dependences of the external quantum efficiency on the active region design are analyzed. It is shown that the use of InGaN/GaN structures as limiting graded-gap short-period superlattices may significantly increase the quantum efficiency.

Tsatsulnikov, A. F., E-mail: Andrew@beam.ioffe.ru; Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Usov, S. O.; Nikolaev, A. E.; Cherkashin, N. A.; Ber, B. Ya.; Kazantsev, D. Yu. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Mizerov, M. N. [Russian Academy of Sciences, Center for Microelectronics, Ioffe Physicotechnical Institute (Russian Federation); Park, Hee Seok [Samsung Electro-Mechanics Co. Ltd. (Korea, Republic of); Hytch, M.; Hue, F. [National Center for Scientific Research, Center for Material Elaboration and Structural Studies (France)

2010-01-15T23:59:59.000Z

259

SciTech Connect: Demonstration Assessment of Light-Emitting Diode (LED)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systems controllerAdditiveBetatronAerogel Deep Bed AdsorptionPost-Top

260

DOE Science Showcase - Light-emitting Diode (LED) Lighting Research | OSTI,  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct: CrudeOffice of Scientific and Technical InformationUS

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures  

SciTech Connect (OSTI)

Efficient semiconductor optical emitters in the deep-ultraviolet spectral window are encountering some of the most deep rooted problems of semiconductor physics. In III-Nitride heterostructures, obtaining short-wavelength photon emission requires the use of wide bandgap high Al composition AlGaN active regions. High conductivity electron (n-) and hole (p-) injection layers of even higher bandgaps are necessary for electrical carrier injection. This approach requires the activation of very deep dopants in very wide bandgap semiconductors, which is a difficult task. In this work, an approach is proposed and experimentally demonstrated to counter the challenges. The active region of the heterostructure light emitting diode uses ultrasmall epitaxially grown GaN quantum dots. Remarkably, the optical emission energy from GaN is pushed from 365?nm (3.4?eV, the bulk bandgap) to below 240?nm (>5.2?eV) because of extreme quantum confinement in the dots. This is possible because of the peculiar bandstructure and band alignments in the GaN/AlN system. This active region design crucially enables two further innovations for efficient carrier injection: Tunnel injection of carriers and polarization-induced p-type doping. The combination of these three advances results in major boosts in electroluminescence in deep-ultraviolet light emitting diodes and lays the groundwork for electrically pumped short-wavelength lasers.

Verma, Jai, E-mail: jverma@nd.edu; Islam, S. M.; Protasenko, Vladimir; Kumar Kandaswamy, Prem; Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-01-13T23:59:59.000Z

262

Bicolor Mn-doped CuInS{sub 2}/ZnS core/shell nanocrystals for white light-emitting diode with high color rendering index  

SciTech Connect (OSTI)

We synthesized bicolor Mn-doped CuInS{sub 2} (CIS)/ZnS core/shell nanocrystals (NCs), in which Mn{sup 2+} ions and the CIS core were separated with a ZnS layer, and both Mn{sup 2+} ions and CIS cores could emit simultaneously. Transmission electron microscopy and powder X-ray diffraction measurements indicated the epitaxial growth of ZnS shell on the CuInS{sub 2} core, and electron paramagnetic resonance spectrum indicated that Mn{sup 2+} ions were on the lattice points of ZnS shell. By integrating these bicolor NCs with commercial InGaN-based blue-emitting diodes, tricolor white light-emitting diodes with color rendering index of 83 were obtained.

Huang, Bo; Dai, Qian; Zhang, Huichao; Liao, Chen; Cui, Yiping; Zhang, Jiayu, E-mail: jyzhang@seu.edu.cn [Advanced Photonic Center, Southeast University, Nanjing 210096 (China); Zhuo, Ningze; Jiang, Qingsong; Shi, Fenghua; Wang, Haibo [Research Institute of Electric Light Source Materials, Nanjing University of Technology, Nanjing 210015 (China)

2014-09-07T23:59:59.000Z

263

Researchers Say They've Solved the Mystery of LED Lighting "Droop...  

Broader source: Energy.gov (indexed) [DOE]

Sciences Team. Despite being cool, ultra-efficient and long lasting, the light-emitting diode (LED) faces a problem called "efficiency droop." New findings from simulations...

264

Nanoscale-accuracy transfer printing of ultra-thin AlInGaN light-emitting diodes onto mechanically flexible substrates  

SciTech Connect (OSTI)

The transfer printing of 2 ?m-thick aluminum indium gallium nitride (AlInGaN) micron-size light-emitting diodes with 150?nm (±14?nm) minimum spacing is reported. The thin AlInGaN structures were assembled onto mechanically flexible polyethyleneterephthalate/polydimethylsiloxane substrates in a representative 16 × 16 array format using a modified dip-pen nano-patterning system. Devices in the array were positioned using a pre-calculated set of coordinates to demonstrate an automated transfer printing process. Individual printed array elements showed blue emission centered at 486?nm with a forward-directed optical output power up to 80??W (355 mW/cm{sup 2}) when operated at a current density of 20?A/cm{sup 2}.

Trindade, A. J., E-mail: antonio.trindade@strath.ac.uk; Guilhabert, B.; Massoubre, D.; Laurand, N.; Gu, E.; Watson, I. M.; Dawson, M. D. [Institute of Photonics, SUPA, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW (United Kingdom)] [Institute of Photonics, SUPA, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW (United Kingdom); Zhu, D.; Humphreys, C. J. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)] [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2013-12-16T23:59:59.000Z

265

Migration enhanced lateral epitaxial overgrowth of AlN and AlGaN for high reliability deep ultraviolet light emitting diodes  

SciTech Connect (OSTI)

We report on the growth of low-defect thick films of AlN and AlGaN on trenched AlGaN/sapphire templates using migration enhanced lateral epitaxial overgrowth. Incoherent coalescence-related defects were alleviated by controlling the tilt angle of growth fronts and by allowing Al adatoms sufficient residence time to incorporate at the most energetically favorable lattice sites. Deep ultraviolet light emitting diode structures (310 nm) deposited over fully coalesced thick AlN films exhibited cw output power of 1.6 mW at 50 mA current with extrapolated lifetime in excess of 5000 hours. The results demonstrate substantial improvement in the device lifetime, primarily due to the reduced density of growth defects.

Jain, R.; Sun, W.; Yang, J.; Shatalov, M.; Hu, X.; Sattu, A.; Lunev, A.; Deng, J.; Shturm, I.; Bilenko, Y.; Gaska, R. [Sensor Electronic Technology, Inc., 1195 Atlas Road, Columbia, South Carolina 29209 (United States); Shur, M. S. [Electrical Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy New York 12180 (United States)

2008-08-04T23:59:59.000Z

266

Experimental verification of effects of barrier dopings on the internal electric fields and the band structure in InGaN/GaN light emitting diodes  

SciTech Connect (OSTI)

We experimentally clarify the effects of barrier dopings on the polarization induced electric fields and the band structure in InGaN/GaN blue light emitting diodes. Both effects were independently verified by using electric field modulated reflectance and capacitance-voltage measurement. It is shown that the Si barrier doping does reduce the polarization induced electric field in the quantum wells. But the benefit of Si-doping is nullified by modification of the band structure and depletion process. With increased number of doped barriers, smaller number of quantum wells remains in the depletion region at the onset of the diffusion process, which can reduce the effective active volume and enhance the electron overflow.

Song, Jung-Hoon; Kim, Tae-Soo; Park, Ki-Nam; Lee, Jin-Gyu [Department of Physics, Kongju National University, Kongju, Chungnam 314-701 (Korea, Republic of); Hong, Soon-Ku, E-mail: soonku@cnu.ac.kr [Department of Advanced Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Cho, Sung-Royng; Lee, Seogwoo; Whan Cho, Meoung [Wasvesquare Co., Inc., Yongin, Gyeonggi 449-863 (Korea, Republic of)

2014-03-24T23:59:59.000Z

267

Using interlayer step-wise triplet transfer to achieve an efficient white organic light-emitting diode with high color-stability  

SciTech Connect (OSTI)

An efficient phosphorescent white organic light emitting-diode with a red-green-blue tri-emitting-layer structure is reported. The host of the red dopant possesses a lower triplet-energy than the green dye. An interlayer step-wise triplet transfer via blue dye ? green dye ? red host ? red dye is achieved. This mechanism allows an efficient triplet harvesting by the three dopants, thus maintaining a balanced white light and reducing energy loss. Moreover, the color stability of the device is improved significantly. The white device not only achieves a peak external quantum efficiency of 21.1?±?0.8% and power efficiency of 37.5?±?1.4?lm/W but shows no color shift over a wide range of voltages.

Wang, Qi [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Department of Electrical Engineering and Computer Sciences, College of Engineering, South Dakota State University, Brookings, South Dakota 57007 (United States); Ma, Dongge, E-mail: mdg1014@ciac.jl.cn; Ding, Junqiao; Wang, Lixiang [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Leo, Karl [Tech. Univ. Dresden, Inst. Angew. Photophys., D-01062 Dresden (Germany); Qiao, Qiquan [Department of Electrical Engineering and Computer Sciences, College of Engineering, South Dakota State University, Brookings, South Dakota 57007 (United States); Jia, Huiping; Gnade, Bruce E. [Department of Materials Science and Engineering and Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083 (United States)

2014-05-12T23:59:59.000Z

268

Top-emission Si-based phosphor organic light emitting diode with Au doped ultrathin n-Si film anode and bottom Al mirror  

SciTech Connect (OSTI)

We report a highly efficient top-emission Si-based phosphor organic light emitting diode (PhOLED) with an ultrathin polycrystalline n-Si:Au film anode and a bottom Al mirror. This anode is formed by magnetron sputtering followed by Ni induced crystallization and then Au diffusion. By optimizing the thickness of the n-Si:Au film anode, the Au diffusion temperature, and the other parameters of the PhOLED, the highest current and power efficiencies of the n-Si:Au film anode PhOLED reached 85{+-}9 cd/A and 80{+-}8 lm/W, respectively, corresponding to an external quantum efficiency of 21{+-}2% and a power conversion efficiency of 15{+-}2%, respectively, which are about 60% and 110% higher than those of the indium tin oxide anode counterpart and 70% and 50% higher than those of the bulk n{sup +}-Si:Au anode counterpart, respectively.

Li, Y. Z.; Xu, W. J.; Ran, G. Z. [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Qin, G. G. [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Key Lab of Semiconductor Materials, CAS, Beijing 100083 (China)

2009-07-20T23:59:59.000Z

269

Enhancement of hole injection and electroluminescence by ordered Ag nanodot array on indium tin oxide anode in organic light emitting diode  

SciTech Connect (OSTI)

We report the enhancement of hole injection and electroluminescence (EL) in an organic light emitting diode (OLED) with an ordered Ag nanodot array on indium-tin-oxide (ITO) anode. Until now, most researches have focused on the improved performance of OLEDs by plasmonic effects of metal nanoparticles due to the difficulty in fabricating metal nanodot arrays. A well-ordered Ag nanodot array is fabricated on the ITO anode of OLED using the nanoporous alumina as an evaporation mask. The OLED device with Ag nanodot arrays on the ITO anode shows higher current density and EL enhancement than the one without any nano-structure. These results suggest that the Ag nanodot array with the plasmonic effect has potential as one of attractive approaches to enhance the hole injection and EL in the application of the OLEDs.

Jung, Mi, E-mail: jmnano00@gmail.com, E-mail: Dockha@kist.re.kr [Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); School of Mechanical Systems Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of); Mo Yoon, Dang; Kim, Miyoung [Korea Printed Electronics Center, Korea Electronics Technology Institute, Jeollabuk-do, 561-844 (Korea, Republic of); Kim, Chulki; Lee, Taikjin; Hun Kim, Jae; Lee, Seok; Woo, Deokha, E-mail: jmnano00@gmail.com, E-mail: Dockha@kist.re.kr [Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lim, Si-Hyung [School of Mechanical Systems Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of)

2014-07-07T23:59:59.000Z

270

Thermally activated delayed fluorescence from {sup 3}n?* to {sup 1}n?* up-conversion and its application to organic light-emitting diodes  

SciTech Connect (OSTI)

Intense n?* fluorescence from a nitrogen-rich heterocyclic compound, 2,5,8-tris(4-fluoro-3-methylphenyl)-1,3,4,6,7,9,9b-heptaazaphenalene (HAP-3MF), is demonstrated. The overlap-forbidden nature of the n?* transition and the higher energy of the {sup 3}??* state than the {sup 3}n?* one lead to a small energy difference between the lowest singlet (S{sub 1}) and triplet (T{sub 1}) excited states of HAP-3MF. Green-emitting HAP-3MF has a moderate photoluminescence quantum yield of 0.26 in both toluene and doped film. However, an organic light-emitting diode containing HAP-3MF achieved a high external quantum efficiency of 6.0%, indicating that HAP-3MF harvests singlet excitons through a thermally activated T{sub 1} ? S{sub 1} pathway in the electroluminescent process.

Li, Jie; Zhang, Qisheng; Nomura, Hiroko [Department of Chemistry and Biochemistry, and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Miyazaki, Hiroshi [Department of Chemistry and Biochemistry, and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Functional Materials Laboratory, Nippon Steel and Sumikin Chemical Co., Ltd, 46–80 Nakabaru, Sakinohama, Tobata, Kitakyushu, Fukuoka 804–8503 (Japan); Adachi, Chihaya, E-mail: adachi@cstf.kyushu-u.ac.jp [Department of Chemistry and Biochemistry, and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)

2014-07-07T23:59:59.000Z

271

Inversion by metalorganic chemical vapor deposition from N- to Ga-polar gallium nitride and its application to multiple quantum well light-emitting diodes  

SciTech Connect (OSTI)

We demonstrate a metalorganic chemical vapor deposition growth approach for inverting N-polar to Ga-polar GaN by using a thin inversion layer grown with high Mg flux. The introduction of this inversion layer allowed us to grow p-GaN films on N-polar GaN thin film. We have studied the dependence of hole concentration, surface morphology, and degree of polarity inversion for the inverted Ga-polar surface on the thickness of the inversion layer. We then use this approach to grow a light emitting diode structure which has the MQW active region grown on the advantageous N-polar surface and the p-layer grown on the inverted Ga-polar surface.

Hosalli, A. M.; Van Den Broeck, D. M.; Bedair, S. M. [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States); Bharrat, D.; El-Masry, N. A. [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)

2013-12-02T23:59:59.000Z

272

Fabrication of ZnO photonic crystals by nanosphere lithography using inductively coupled-plasma reactive ion etching with CH{sub 4}/H{sub 2}/Ar plasma on the ZnO/GaN heterojunction light emitting diodes  

SciTech Connect (OSTI)

This article reports fabrication of n-ZnO photonic crystal/p-GaN light emitting diode (LED) by nanosphere lithography to further booster the light efficiency. In this article, the fabrication of ZnO photonic crystals is carried out by nanosphere lithography using inductively coupled plasma reactive ion etching with CH{sub 4}/H{sub 2}/Ar plasma on the n-ZnO/p-GaN heterojunction LEDs. The CH{sub 4}/H{sub 2}/Ar mixed gas gives high etching rate of n-ZnO film, which yields a better surface morphology and results less plasma-induced damages of the n-ZnO film. Optimal ZnO lattice parameters of 200 nm and air fill factor from 0.35 to 0.65 were obtained from fitting the spectrum of n-ZnO/p-GaN LED using a MATLAB code. In this article, we will show our recent result that a ZnO photonic crystal cylinder has been fabricated using polystyrene nanosphere mask with lattice parameter of 200 nm and radius of hole around 70 nm. Surface morphology of ZnO photonic crystal was examined by scanning electron microscope.

Chen, Shr-Jia; Chang, Chun-Ming; Kao, Jiann-Shiun; Chen, Fu-Rong; Tsai, Chuen-Horng [Engineering and System Science, National Tsing Hua University, Hsinchu, 30013 Taiwan (China); Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, 300 Taiwan (China); Engineering and System Science, National Tsing Hua University, Hsinchu, 30013 Taiwan (China)

2010-07-15T23:59:59.000Z

273

Depth-resolved confocal micro-Raman spectroscopy for characterizing GaN-based light emitting diode structures  

SciTech Connect (OSTI)

In this work, we demonstrate that depth-resolved confocal micro-Raman spectroscopy can be used to characterize the active layer of GaN-based LEDs. By taking the depth compression effect due to refraction index mismatch into account, the axial profiles of Raman peak intensities from the GaN capping layer toward the sapphire substrate can correctly match the LED structural dimension and allow the identification of unique Raman feature originated from the 0.3 ?m thick active layer of the studied LED. The strain variation in different sample depths can also be quantified by measuring the Raman shift of GaN A{sub 1}(LO) and E{sub 2}(high) phonon peaks. The capability of identifying the phonon structure of buried LED active layer and depth-resolving the strain distribution of LED structure makes this technique a potential optical and remote tool for in operando investigation of the electronic and structural properties of nitride-based LEDs.

Chen, Wei-Liang; Lee, Yu-Yang; Chang, Yu-Ming, E-mail: ymchang@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China)] [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Chang, Chiao-Yun; Huang, Huei-Min; Lu, Tien-Chang [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)] [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)

2013-11-15T23:59:59.000Z

274

Development of a cost effective surface-patterned transparent conductive coating as top-contact of light emitting diodes  

SciTech Connect (OSTI)

Sol-gel process has been used to form indium zinc oxide films using an optimized combination of zinc to indium concentration in the precursor solutions. Different structures, like one (1D) and two-dimensional (2D) gratings and diffractive optical elements (DOEs) in the form of Fresnel lens are fabricated on the film surface of proposed top metal contact of LED by imprint soft lithography technique. These structures can enhance the LED's light extraction efficiency (LEE) or can shape the output beam pattern, respectively. Several characterizations are done to analyze the material and structural properties of the films. The presence of 1D and 2D gratings as well as DOEs is confirmed from field emission scanning electron and atomic force microscopes analyses. Although, X-ray diffraction shows amorphous nature of the film, but transmission electron microscopy study shows that it is nano crystalline in nature having fine particles (?8?nm) of hexagonal ZnO. Shrinkage behaviour of gratings as a function of curing temperature is explained by Fourier transform infra-red spectra and thermo gravimetric-differential thermal analysis. The visible transmission and sheet resistance of the sample are found comparable to tin doped indium oxide (ITO). Therefore, the film can compete as low cost substitute of ITO as top metal contact of LEDs.

Haldar, Arpita [Department of Applied Optics and Photonics, University of Calcutta, Kolkata-700009 (India); Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Bera, Susanta; Jana, Sunirmal, E-mail: sjana@cgcri.res.in, E-mail: srirajib@yahoo.com [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Bhattacharya, Kallol; Chakraborty, Rajib, E-mail: sjana@cgcri.res.in, E-mail: srirajib@yahoo.com [Department of Applied Optics and Photonics, University of Calcutta, Kolkata-700009 (India)

2014-05-21T23:59:59.000Z

275

Systematic Investigation of Nanoscale Adsorbate Effects at Organic Light-Emitting diode Interfaces. Interfacial Structure-Charge Injection-Luminance Relationships  

SciTech Connect (OSTI)

Molecule-scale structure effects at indium tin oxide (ITO) anode-hole transport layer (HTL) interfaces in organic light-emitting diode (OLED) heterostructures are systematically probed via a self-assembly approach. A series of ITO anode-linked silyltriarylamine precursors differing in aryl group and linker density are synthesized for this purpose and used to probe the relationship between nanoscale interfacial chemical structure and charge-injection/electroluminescence properties. These precursors form conformal and largely pinhole-free self-assembled monolayers (SAMs) on the ITO anode surface with angstrom-level thickness control. Deposition of a HTL on top of the SAMs places the probe molecules precisely at the anode-HTL interface. OLEDs containing ITO/SAM/HTL configurations have dramatically varied hole-injection magnitudes and OLED responses. These can be correlated with the probe molecular structures and electrochemically derived heterogeneous electron-transfer rates for such triarylamine fragments. The large observed interfacial molecular structure effects offer an approach to tuning OLED hole-injection flux over 1-2 orders of magnitude, resulting in up to 3-fold variations in OLED brightness at identical bias and up to a 2 V driving voltage reduction at identical brightness. Very bright and efficient ({approx}70 000 cd/m{sup 2}, {approx}2.5% forward external quantum efficiency, {approx}11 lm/W power efficiency) Alq (tris(8-hydroxyquinolinato)aluminum(III))-based OLEDs can thereby be fabricated.

Huang,Q.; Li, J.; Evmenenko, G.; Dutta, P.; Marks, T.

2006-01-01T23:59:59.000Z

276

Numerical study of the influence of applied voltage on the current balance factor of single layer organic light-emitting diodes  

SciTech Connect (OSTI)

Current balance factor (CBF) value, the ratio of the recombination current density and the total current density of a device, has an important function in fluorescence-based organic light-emitting diodes (OLEDs), as well as in the performance of the organic electrophosphorescent devices. This paper investigates the influence of the applied voltage of a device on the CBF value of single layer OLED based on the numerical model of a bipolar single layer OLED with organic layer trap free and without doping. Results show that the largest CBF value can be achieved when the electron injection barrier (?{sub n}) is equal to the hole injection barrier (?{sub p}) in the lower voltage region at any instance. The largest CBF in the higher voltage region can be achieved in the case of ?{sub n}?>??{sub p} under the condition of electron mobility (?{sub 0n}) > hole mobility (?{sub 0p}), whereas the result for the case of ?{sub 0n}?

Lu, Fei-ping, E-mail: lufp-sysu@163.com; Liu, Xiao-bin; Xing, Yong-zhong [College of Physics and Information Science, Tianshui Normal University, Tianshui 741001 (China)

2014-04-28T23:59:59.000Z

277

Distinguishing triplet energy transfer and trap-assisted recombination in multi-color organic light-emitting diode with an ultrathin phosphorescent emissive layer  

SciTech Connect (OSTI)

An ultrathin layer of deep-red phosphorescent emitter tris(1-phenylisoquinoline) iridium (III) (Ir(piq){sub 3}) is inserted within different positions of the electron blocking layer fac-tris (1-phenylpyrazolato-N,C{sup 2?})-iridium(III) (Ir(ppz){sub 3}) to distinguish the contribution of the emission from the triplet exciton energy transfer/diffusion from the adjacent blue phosphorescent emitter and the trap-assisted recombination from the narrow band-gap emitter itself. The charge trapping effect of the narrow band-gap deep-red emitter which forms a quantum-well-like structure also plays a role in shaping the electroluminescent characteristics of multi-color organic light-emitting diodes. By accurately controlling the position of the ultrathin sensing layer, it is considerably easy to balance the white emission which is quite challenging for full-color devices with multiple emission zones. There is nearly no energy transfer detectable if 7 nm thick Ir(ppz){sub 3} is inserted between the blue phosphorescent emitter and the ultrathin red emitter.

Xue, Qin, E-mail: xueqin19851202@163.com; Liu, Shouyin [Department of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Xie, Guohua; Chen, Ping; Zhao, Yi; Liu, Shiyong [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2014-03-21T23:59:59.000Z

278

Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions  

SciTech Connect (OSTI)

In this paper, a novel type of white-light organic light emitting diode (OLED) with high color stability was reported, in which the yellow-light emission layer of (4,4{sup ?}-N,N{sup ?}-dicarbazole)biphenyl (CBP) : tris(2-phenylquinoline-C2,N{sup ?})iridium(III) (Ir(2-phq){sub 3}) was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylamino)pheny1]cyclohexane (TAPC) : bis[4,6-(di-fluorophenyl)-pyridinato-N,C2{sup ?}]picolinate (FIrpic) and tris[3-(3-pyridyl)mesityl]borane (3TPYMB):FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m{sup 2}. More important, it realized very stable white-light emission, and its CIE(x, y) coordinates only shift from (0.34, 0.37) to (0.33, 0.37) as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

Hua, Wang, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Du, Xiaogang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China) [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Su, Wenming, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Zhang, Dongyu [Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China)] [Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China); Lin, Wenjing [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China) [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China)

2014-02-15T23:59:59.000Z

279

Permanent polarization and charge distribution in organic light-emitting diodes (OLEDs): Insights from near-infrared charge-modulation spectroscopy of an operating OLED  

SciTech Connect (OSTI)

Vapor-deposited Alq{sub 3} layers typically possess a strong permanent electrical polarization, whereas NPB layers do not. (Alq{sub 3} is tris(8-quinolinolato)aluminum(III); NPB is 4,4?-bis[N-(1-naphthyl)-N-phenylamino]biphenyl.) The cause is a net orientation of the Alq{sub 3} molecules with their large dipole moments. Here we report on consequences for an organic light-emitting diode (OLED) with an NPB hole-transport layer and Alq{sub 3} electron-transport layer. The discontinuous polarization at the NPB|Alq{sub 3} interface has the same effect as a sheet of immobile negative charge there. It is more than compensated by a large concentration of injected holes (NPB{sup +}) when the OLED is running. We discuss the implications and consequences for the quantum efficiency and the drive voltage of this OLED and others. We also speculate on possible consequences of permanent polarization in organic photovoltaic devices. The concentration of NPB{sup +} was measured by charge-modulation spectroscopy (CMS) in the near infrared, where the NPB{sup +} has a strong absorption band, supplemented by differential-capacitance and current-voltage measurements. Unlike CMS in the visible, this method avoids complications from modulation of the electroluminescence and electroabsorption.

Marchetti, Alfred P.; Haskins, Terri L.; Young, Ralph H.; Rothberg, Lewis J. [Department of Chemistry, University of Rochester, Rochester, New York 14627 (United States)

2014-03-21T23:59:59.000Z

280

Surface plasmon dispersion engineering via double-metallic AU/AG layers for nitride light-emitting diodes  

DOE Patents [OSTI]

A double-metallic deposition process is used whereby adjacent layers of different metals are deposited on a substrate. The surface plasmon frequency of a base layer of a first metal is tuned by the surface plasmon frequency of a second layer of a second metal formed thereon. The amount of tuning is dependent upon the thickness of the metallic layers, and thus tuning can be achieved by varying the thicknesses of one or both of the metallic layers. In a preferred embodiment directed to enhanced LED technology in the green spectrum regime, a double-metallic Au/Ag layer comprising a base layer of gold (Au) followed by a second layer of silver (Ag) formed thereon is deposited on top of InGaN/GaN quantum wells (QWs) on a sapphire/GaN substrate.

Tansu, Nelson; Zhao, Hongping; Zhang, Jing; Liu, Guangyu

2014-04-01T23:59:59.000Z

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281

LED Manufacturing Process Modifications Will Boost Quality and  

E-Print Network [OSTI]

2012 The Issue Highly energyefficient LightEmitting Diode (LED) lighting products have made great process that will enable LED manufacturers to produce higher quality, energyefficient products at lower

282

Measurement of the absorption coefficient for light laterally propagating in light-emitting diode structures with In{sub 0.2}Ga{sub 0.8}N/GaN quantum wells  

SciTech Connect (OSTI)

A procedure for measuring the absorption coefficient for light propagating parallel to the surface of a GaN-based light emitting diode chip on a sapphire substrate is suggested. The procedure implies the study of emission from one end face of the chip as the opposite end face is illuminated with a light emitting diode. The absorption coefficient is calculated from the ratio between the intensities of emission emerging from the end faces of the sapphire substrate and the epitaxial layer. From the measurements for chips based on p-GaN/In{sub 0.2}Ga{sub 0.8}N/n-GaN structures, the lateral absorption coefficient is determined at a level of (23 {+-} 3)cm{sup -1} at a wavelength of 465 nm. Possible causes for the discrepancy between the absorption coefficients determined in the study and those reported previously are analyzed.

Lelikov, Yu. S.; Bochkareva, N. I.; Gorbunov, R. I.; Martynov, I. A.; Rebane, Yu. T.; Tarkin, D. V.; Shreter, Yu. G. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: YShreter@mail.ioffe.ru

2008-11-15T23:59:59.000Z

283

Luminescence properties of light-emitting diodes based on GaAs with the up-conversion Y{sub 2}O{sub 2}S:Er,Yb luminophor  

SciTech Connect (OSTI)

Y{sub 2}O{sub 2}S luminophors doped with Er{sup 3+} and Yb{sup 3+} ions are produced by means of solid-phase synthesis and deposited onto standard AL123A infrared light-emitting diodes. When excited with 940 nm radiation from a light-emitting diode, the structures exhibit intense visible up-conversion luminescence. A maximal brightness of 2340 cd/m{sup 2} of green and red up-conversion luminescence at corresponding wavelengths around 550 and 600 nm is observed for the Y{sub 2}O{sub 2}S compound doped with 2 at % Er{sup 3+} ions and 6 at % Yb{sup 3+} ions. The ratio of the intensity of green (or red) up-conversion luminescence to the intensity of infrared Stokes luminescence increases with increasing applied voltage. The efficiency of visible emission of the light-emitting diode structures is {eta} = 1.2 lm/W at an applied voltage of 1.5 V.

Gruzintsev, A. N., E-mail: gran@ipmt-hpm.ac.ru [Russian Academy of Sciences, Institute of Problems of Microelectronics Technology (Russian Federation); Barthou, C.; Benalloul, P. [Institute des NanoSciences (France)

2008-03-15T23:59:59.000Z

284

Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces  

SciTech Connect (OSTI)

We report on green (550–560?nm) electroluminescence (EL) from (Al{sub 0.5}Ga{sub 0.5}){sub 0.5}In{sub 0.5}P-(Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P double p-i-n heterostructures with monolayer-scale GaP insertions in the cladding layers and light-emitting diodes based thereupon. The structures are grown side-by-side on high-index and (100) GaAs substrates by molecular beam epitaxy. At moderate current densities (?500?A/cm{sup 2}), the EL intensity of the structures is comparable for all substrate orientations. Opposite to the (100)-grown strictures, the EL spectra of (211) and (311)-grown devices are shifted towards shorter wavelengths (?550?nm at room temperature). At high current densities (>1?kA/cm{sup 2}), a much higher EL intensity is achieved for the devices grown on high-index substrates. The integrated intensity of (311)-grown structures gradually saturates at current densities above 4?kA/cm{sup 2}, whereas no saturation is revealed for (211)-grown structures up to the current densities above 14?kA/cm{sup 2}. We attribute the effect to the surface orientation-dependent engineering of the GaP band structure, which prevents the escape of the nonequilibrium electrons into the indirect conduction band minima of the p-doped (Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P cladding layers.

Ledentsov, N. N., E-mail: nikolay.ledentsov@v-i-systems.com; Shchukin, V. A. [VI Systems GmbH, Hardenbergstr. 7, Berlin D-10623 (Germany); Lyytikäinen, J.; Okhotnikov, O. [Optoelectronics Research Centre, Tampere University of Technology, Tampere FI-33720 (Finland); Shernyakov, Yu. M.; Payusov, A. S.; Gordeev, N. Yu.; Maximov, M. V. [A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Schlichting, S.; Nippert, F.; Hoffmann, A. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, Berlin D-10623 (Germany)

2014-11-03T23:59:59.000Z

285

Comparison of light out-coupling enhancements in single-layer blue-phosphorescent organic light emitting diodes using small-molecule or polymer hosts  

SciTech Connect (OSTI)

Single-layer blue phosphorescence organic light emitting diodes (OLEDs) with either small-molecule or polymer hosts are fabricated using solution process and the performances of devices with different hosts are investigated. The small-molecule device exhibits luminous efficiency of 14.7?cd/A and maximum power efficiency of 8.39?lm/W, which is the highest among blue phosphorescence OLEDs with single-layer solution process and small molecular hosts. Using the same solution process for all devices, comparison of light out-coupling enhancement, with brightness enhancement film (BEF), between small-molecule and polymer based OLEDs is realized. Due to different dipole orientation and anisotropic refractive index, polymer-based OLEDs would trap less light than small molecule-based OLEDs internally, about 37% better based simulation results. In spite of better electrical and spectroscopic characteristics, including ambipolar characteristics, higher carrier mobility, higher photoluminescence quantum yield, and larger triplet state energy, the overall light out-coupling efficiency of small molecule-based devices is worse than that of polymer-based devices without BEF. However, with BEF for light out-coupling enhancement, the improved ratio in luminous flux and luminous efficiency for small molecule based device is 1.64 and 1.57, respectively, which are significantly better than those of PVK (poly-9-vinylcarbazole) devices. In addition to the theoretical optical simulation, the experimental data also confirm the origins of differential light-outcoupling enhancement. The maximum luminous efficiency and power efficiency are enhanced from 14.7?cd/A and 8.39?lm/W to 23?cd/A and 13.2?lm/W, respectively, with laminated BEF, which are both the highest so far for single-layer solution-process blue phosphorescence OLEDs with small molecule hosts.

Chang, Yung-Ting [Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Taiwan (China); Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan 10617, Taiwan (China); Liu, Shun-Wei [Department of Electronic Engineering, Mingchi University of Technology, New Taipei, Taiwan 24301, Taiwan (China); Yuan, Chih-Hsien; Lee, Chih-Chien [Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan 10607, Taiwan (China); Ho, Yu-Hsuan; Wei, Pei-Kuen [Research Center for Applied Science Academia Sinica, Taipei, Taiwan 11527, Taiwan (China); Chen, Kuan-Yu [Chilin Technology Co., LTD, Tainan City, Taiwan 71758, Taiwan (China); Lee, Yi-Ting; Wu, Min-Fei; Chen, Chin-Ti, E-mail: cchen@chem.sinica.edu.tw, E-mail: chihiwu@cc.ee.ntu.edu.tw [Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Taiwan (China); Wu, Chih-I, E-mail: cchen@chem.sinica.edu.tw, E-mail: chihiwu@cc.ee.ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan 10617, Taiwan (China)

2013-11-07T23:59:59.000Z

286

Light emitting ceramic device  

DOE Patents [OSTI]

A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, is herein claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

Valentine, Paul; Edwards, Doreen D.; Walker, Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

2010-05-18T23:59:59.000Z

287

An optimal light-extracting overlayer, inspired by the lantern of a Photuris firefly, to improve the external efficiency of existing light-emitting diodes  

E-Print Network [OSTI]

Actual light emission diodes (LED) have most often good internal efficiencies but poor external efficiencies due to total internal reflection at the air interface. In this paper the design, fabrication and characterization of a bioinspired overlayer deposited on a GaN LED is investigated. The purpose of this overlayer is to improve light extraction into air, after the photons have been generated in the diode's high refractive-index active material. The layer design is inspired by the microstructure found in the firefly Photuris sp., described by Bay et al. : a surface with an asymmetrical triangular profile (a "factory-roof" shape), developed on the scale of a few micrometers, thus somewhat larger than usually suggested in the related literature. The profile of the overlayer corrugated surface of the coating film was copied from the natural model. Yet, the actual dimensions and material composition have been optimized to take into account the high refractive index of the GaN diode stack. The optimization proc...

Bay, Annick; Sarrazin, Michael; Belarouci, Ali; Aimez, Vincent; Francis, Laurent A; Vigneron, Jean Pol

2012-01-01T23:59:59.000Z

288

Belgirate, Italy, 28-30 September 2005 MECHANISM AND THERMAL EFFECT OF DELAMINATION IN LIGHT-EMITTING  

E-Print Network [OSTI]

for the investigation of the thermal behavior of the delaminated LEDs. Increase of thermal resistance with the degreeBelgirate, Italy, 28-30 September 2005 MECHANISM AND THERMAL EFFECT OF DELAMINATION IN LIGHT-EMITTING DIODE PACKAGES Jianzheng Hu, Lianqiao Yang, and Moo Whan Shin Department of Materials Science

Paris-Sud XI, Université de

289

Fabrication of InGaP LEDs on a graded buffer substrate  

E-Print Network [OSTI]

Introduction: Computer display panels create a vast color palette by combining color from three light emitting diodes (LEDs), each producing red, green, or blue light. The light from these three LEDs is chosen so that the ...

Martínez, Josué F

2007-01-01T23:59:59.000Z

290

Have You Used LED Lighting? Tell Us About It. | Department of...  

Broader source: Energy.gov (indexed) [DOE]

It. May 7, 2009 - 5:00am Addthis This week, John shared his experiences with light-emitting diode (LED) lighting. In a future blog, he'll share more about LED lighting. Have you...

291

The light-emitting diode (LED) is an fairly new kind of light source found currently in  

E-Print Network [OSTI]

this technology an ideal replacement for less efficient incandescent light sources, particularly in applications elevator lighting has the potential to achieve 25 percent greater efficiency than current incandescent ILLUMINATION LEVELS SIMILAR TO THOSE OF INCANDESCENT FIXTURES WHILE CUTTING ENERGY USE 45 PERCENT. ELEVATOR

292

Demonstration Assessment of Light-Emitting Diode (LED) Retrofit Lamps at Intercontinental Hotel in San Francisco, CA  

SciTech Connect (OSTI)

This document is a report of observations and results obtained from a lighting demonstration project conducted under the U.S. Department of Energy (DOE) GATEWAY Demonstration Program. The program supports demonstrations of high-performance solid-state lighting (SSL) products in order to develop empirical data and experience with in-the-field applications of this advanced lighting technology. The DOE GATEWAY Demonstration Program focuses on providing a source of independent, third-party data for use in decision-making by lighting users and professionals; this data should be considered in combination with other information relevant to the particular site and application under examination. Each GATEWAY Demonstration compares SSL products against the incumbent technologies used in that location. Depending on available information and circumstances, the SSL product may also be compared to alternate lighting technologies. Though products demonstrated in the GATEWAY program have been prescreened and tested to verify their actual performance, DOE does not endorse any commercial product or in any way guarantee that users will achieve the same results through use of these products.

Miller, Naomi J.; Curry, Ku'Uipo J.

2010-11-01T23:59:59.000Z

293

Potential Environmental Impacts from the Metals in Incandescent, Compact Fluorescent Lamp (CFL), and Light-Emitting Diode (LED)  

E-Print Network [OSTI]

the lighting products are to be categorized as hazardous waste under existing U.S. federal and California state in lighting products without compromising their performance and useful lifespan. INTRODUCTION The U.S. Energy to increase energy efficiency for general lighting. Therefore, consumers are replacing incandescent light

Short, Daniel

294

MOF Coating a Promising Path to White LEDs  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(MOF); the structure was determined at Beamline 11.3.1. Coating a blue light-emitting diode (LED) with this compound readily generates white light with high luminous...

295

Demonstrating LED and Fiber Optic Lighting in Commissary Applications  

Broader source: Energy.gov [DOE]

Presentation—given at the Federal Utility Partnership Working Group (FUPWG) Fall 2008 meeting—covers goals of the project and applications for light-emitting diodes (LEDs) and fiber optic lighting.

296

Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)  

SciTech Connect (OSTI)

Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3- hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A thin LiF layer serves typically as the electron injection layer in OLEDs and electron collection interlayer in the OSCs. However, several reports showed that it can also assist in holeinjection in OLEDs. Here we first demonstrate that it assists hole-collection in OSCs, which is more obvious after air-plasma treatment, and explore this intriguing dual role. For OLEDs, we focus on solution processing methods to fabricate highly efficient phosphorescent OLEDs. First, we investigated OLEDs with a polymer host matrix, and enhanced charge injection by adding hole- and electron-transport materials into the system. We also applied a hole-blocking and electron-transport material to prevent luminescence quenching by the cathode. Finally, we substituted the polymer host by a small molecule, to achieve more efficient solution processed small molecular OLEDs (SMOLEDs); this approach is cost-effective in comparison to the more common vacuum thermal evaporation. All these studies help us to better understand the underlying relationship between the organic semiconductor materials and the OSCs and OLEDs’ performance and will subsequently assist in further enhancing the efficiencies of OSCs and OLEDs. With better efficiency and longer lifetime, the OSCs and OLEDs will be competitive with their inorganic counterparts.

Xiao, Teng

2012-04-27T23:59:59.000Z

297

E-Print Network 3.0 - advanced semiconductor light-emitting Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Quantum Dot Sol-Gel Nanocomposites (patent pending) n Nanocrystal Quantum Dot Light Emitting Diode (patent... (CRADA) Business Opportunities LANL's quantum dot portfolio includes...

298

2014-05-16 Issuance: Test Procedures for Integrated Light-Emitting...  

Broader source: Energy.gov (indexed) [DOE]

16 Issuance: Test Procedures for Integrated Light-Emitting Diode Lamps; Supplemental Notice of Proposed Rulemaking 2014-05-16 Issuance: Test Procedures for Integrated...

299

LED lamp  

DOE Patents [OSTI]

There is herein described a lamp for providing white light comprising a plurality of light sources positioned on a substrate. Each of said light sources comprises a blue light emitting diode (LED) and a dome that substantially covers said LED. A first portion of said blue light from said LEDs is transmitted through said domes and a second portion of said blue light is converted into a red light by a first phosphor contained in said domes. A cover is disposed over all of said light sources that transmits at least a portion of said red and blue light emitted by said light sources. The cover contains a second phosphor that emits a yellow light in response to said blue light. The red, blue and yellow light combining to form the white light and the white light having a color rendering index (CRI) of at least about 80.

Galvez, Miguel; Grossman, Kenneth; Betts, David

2013-11-12T23:59:59.000Z

300

Transcranial LED therapy for cognitive dysfunction in chronic, mild traumatic brain injury: Two case reports  

E-Print Network [OSTI]

Two chronic, traumatic brain injury (TBI) cases are presented, where cognitive function improved following treatment with transcranial light emitting diodes (LEDs). At age 59, P1 had closed-head injury from a motor vehicle ...

Hamblin, Michael R.

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Deposition of colloidal quantum dots by microcontact printing for LED display technology  

E-Print Network [OSTI]

This thesis demonstrates a new deposition method of colloidal quantum dots within a quantum dot organic light-emitting diode (QD-LED). A monolayer of quantum dots is microcontact printed as small as 20 ,Lm lines as well ...

Kim, LeeAnn

2006-01-01T23:59:59.000Z

302

Psychophysical evaluations of modulated color rendering for energy performance of LED-based architectural lighting  

E-Print Network [OSTI]

This thesis is focused on the visual perception evaluation of colors within an environment of a highly automated lighting control strategy. Digitally controlled lighting systems equipped with light emitting diodes, LEDs, ...

Thompson, Maria do Rosário

2007-01-01T23:59:59.000Z

303

The Laser DiodeThe Laser Diode Jason HillJason Hill  

E-Print Network [OSTI]

a Laser Diode Works Edge Emitting Laser Diode Operates similar to a Light Emitting DiodeOperates similar to a Light Emitting Diode Active medium is a semiconductor pActive medium is a semiconductor p--n junctionn Operates similar to a Light Emitting DiodeOperates similar to a Light Emitting Diode Active medium

La Rosa, Andres H.

304

Close-packed array of light emitting devices  

DOE Patents [OSTI]

A close-packed array of light emitting diodes includes a nonconductive substrate having a plurality of elongate channels extending therethrough from a first side to a second side, where each of the elongate channels in at least a portion of the substrate includes a conductive rod therein. The conductive rods have a density over the substrate of at least about 1,000 rods per square centimeter and include first conductive rods and second conductive rods. The close-packed array further includes a plurality of light emitting diodes on the first side of the substrate, where each light emitting diode is in physical contact with at least one first conductive rod and in electrical contact with at least one second conductive rod.

Ivanov, Ilia N.; Simpson, John T.

2013-04-09T23:59:59.000Z

305

Efficient semiconductor light-emitting device and method  

DOE Patents [OSTI]

A semiconductor light-emitting device and method. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL).

Choquette, Kent D. (Albuquerque, NM); Lear, Kevin L. (Albuquerque, NM); Schneider, Jr., Richard P. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

306

Efficient semiconductor light-emitting device and method  

DOE Patents [OSTI]

A semiconductor light-emitting device and method are disclosed. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL). 12 figs.

Choquette, K.D.; Lear, K.L.; Schneider, R.P. Jr.

1996-02-20T23:59:59.000Z

307

Design and fabrication of high-index-contrast self-assembled texture for light extraction enhancement in LEDs  

E-Print Network [OSTI]

We developed a high-index-contrast photonic structure for improving the light extraction efficiency of light-emitting diodes (LEDs) by a self-assembly approach. In this approach, a two-dimensional grating can be ...

Sheng, Xing

308

Today LED Holiday Lights, Tomorrow the World?  

SciTech Connect (OSTI)

This article for The APEM Advantage, the quarterly newsletter of the Association of Professional Energy Managers (APEM) describes the recent increase in the popularity of light emitting diode (LED) lighting and compares LED light output with that of incandescent and compact fluorescent lighting.

Gordon, Kelly L.

2004-12-20T23:59:59.000Z

309

Low Voltage, Low Power Organic Light Emitting Transistors for AMOLED Displays  

SciTech Connect (OSTI)

Low voltage, low power dissipation, high aperture ratio organic light emitting transistors are demonstrated. The high level of performance is enabled by a carbon nanotube source electrode that permits integration of the drive transistor and the organic light emitting diode into an efficient single stacked device. Given the demonstrated performance, this technology could break the technical logjam holding back widespread deployment of active matrix organic light emitting displays at flat panel screen sizes.

McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; Reynolds, J. R. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville

2011-01-01T23:59:59.000Z

310

Cathode encapsulation of organic light emitting diodes by atomic layer deposited Al{sub 2}O{sub 3} films and Al{sub 2}O{sub 3}/a-SiN{sub x}:H stacks  

SciTech Connect (OSTI)

Al{sub 2}O{sub 3} thin films synthesized by plasma-enhanced atomic layer deposition (ALD) at room temperature (25 deg. C) have been tested as water vapor permeation barriers for organic light emitting diode devices. Silicon nitride films (a-SiN{sub x}:H) deposited by plasma-enhanced chemical vapor deposition served as reference and were used to develop Al{sub 2}O{sub 3}/a-SiN{sub x}:H stacks. On the basis of Ca test measurements, a very low intrinsic water vapor transmission rate of {<=} 2 x 10{sup -6} g m{sup -2} day{sup -1} and 4 x 10{sup -6} g m{sup -2} day{sup -1} (20 deg. C/50% relative humidity) were found for 20-40 nm Al{sub 2}O{sub 3} and 300 nm a-SiN{sub x}:H films, respectively. The cathode particle coverage was a factor of 4 better for the Al{sub 2}O{sub 3} films compared to the a-SiN{sub x}:H films and an average of 0.12 defects per cm{sup 2} was obtained for a stack consisting of three barrier layers (Al{sub 2}O{sub 3}/a-SiN{sub x}:H/Al{sub 2}O{sub 3}).

Keuning, W.; Weijer, P. van de; Lifka, H.; Kessels, W. M. M.; Creatore, M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Philips Research Laboratories, High Tech Campus 4, P.O. Box WAG12, 5656 AE Eindhoven (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2012-01-15T23:59:59.000Z

311

Bias dependence and correlation of the cathodoluminescence and electron beam induced current from an InGaN/GaN light emitting diode  

SciTech Connect (OSTI)

Micron-scale mapping has been employed to study a contacted InGaN/GaN LED using combined electroluminescence (EL), cathodoluminescence (CL), and electron beam induced current (EBIC). Correlations between parameters, such as the EBIC and CL intensity, were studied as a function of applied bias. The CL and EBIC maps reveal small areas, 2–10??m in size, which have increased nonradiative recombination rate and/or a lower conductivity. The CL emission from these spots is blue shifted, by 30–40?meV. Increasing the reverse bias causes the size of the spots to decrease, due to competition between in-plane diffusion and drift in the growth direction. EL mapping shows large bright areas (?100??m) which also have increased EBIC, indicating domains of increased conductivity in the p and/or n-GaN.

Wallace, M. J.; Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Kappers, M. J.; Oehler, F.; Oliver, R. A.; Humphreys, C. J. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom); Hopkins, M. A.; Sivaraya, S.; Allsopp, D. W. E. [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom)

2014-07-21T23:59:59.000Z

312

Organic light emitting diodes with structured electrodes  

DOE Patents [OSTI]

A cathode that contain nanostructures that extend into the organic layer of an OLED has been described. The cathode can have an array of nanotubes or a layer of nanoclusters extending out from its surface. In another arrangement, the cathode is patterned and etched to form protruding nanostructures using a standard lithographic process. Various methods for fabricating these structures are provided, all of which are compatible with large-scale manufacturing. OLEDs made with these novel electrodes have greatly enhanced electron injection, have good environmental stability.

Mao, Samuel S.; Liu, Gao; Johnson, Stephen G.

2012-12-04T23:59:59.000Z

313

LASER DIODE TECHNOLOGY AND APPLICATIONS Submitted to  

E-Print Network [OSTI]

and a normal diode and a light emitting diode. I will also define the terms homojunction and heterojunction, and is the main source of light in a light-emitting diode. Under suitable conditions, the electron and the hole

La Rosa, Andres H.

314

DUAL USE OF LEDS: SIGNALING AND COMMUNICATIONS IN ITS Grantham Pang, Chi-ho Chan, Hugh Liu, Thomas Kwan  

E-Print Network [OSTI]

of light-emitting diodes (LEDs) over incandescent lights is well-supported. This is due to their high shown that the high brightness LEDs are significantly brighter than the incandescent lights lights with LEDs is a reduction in power consumption [7]. In addition, incandescent traffic signals burn

Pang, Grantham

315

Research Resources and Centers Research plays an integral role in Rensselaer's vision of the  

E-Print Network [OSTI]

in materials, devices, systems, nanotechnology, light emitting diodes (LEDs), organic light emitting diodes

Varela, Carlos

316

Physical properties and design of light-emitting devices based on organic materials and nanoparticles  

E-Print Network [OSTI]

This thesis presents the detailed experimental and theoretical characterization of light-emitting devices (LEDs) based on organic semiconductors and colloidal quantum dots (QDs). This hybrid material system has several ...

Anikeeva, Polina Olegovna

2009-01-01T23:59:59.000Z

317

Fabrication and optimization of light emitting devices with core-shell quantum dots  

E-Print Network [OSTI]

Quantum dot light emitting devices (QD-LEDs) are promising options for the next generation of solid state lighting, color displays, and other optoelectronic applications. Overcoating quantum dots (QDs) -- semiconducting ...

Song, Katherine Wei

2013-01-01T23:59:59.000Z

318

White light-emitting organic electroluminescent devices  

DOE Patents [OSTI]

A light-emitting device comprises a light-emitting member, which comprises two electrodes, at least two organic electroluminescent ("EL") materials disposed between the electrodes, a charge blocking material disposed between the electrodes, and at least one photoluminescent ("PL") material. The light-emitting member emits electromagnetic ("EM") radiation having a first spectrum in response to a voltage applied across the two electrodes. The PL material absorbs a portion of the EM radiation emitted by the light-emitting member and emits EM radiation having second spectrum different than the first spectrum. Each of the organic EL materials emits EM radiation having a wavelength range selected from the group consisting of blue and red wavelength ranges.

Shiang, Joseph John; Duggal, Anil Raj; Parthasarathy, Gautam

2006-06-20T23:59:59.000Z

319

Stable blue phosphorescent organic light emitting devices  

DOE Patents [OSTI]

Novel combination of materials and device architectures for organic light emitting devices is provided. An organic light emitting device, is provided, having an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer includes a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm, and a radiative phosphorescent lifetime less than 1 microsecond. Preferably, the phosphorescent emissive dopant includes a ligand having a carbazole group.

Forrest, Stephen R.; Thompson, Mark; Giebink, Noel

2014-08-26T23:59:59.000Z

320

LED Light Fixture Project FC1 Director's Conference Room: Life Cycle Cost and Break-even Analysis  

E-Print Network [OSTI]

. A light-emitting diode (LED) is a solid-state lighting source that switches on instantly, is readilyLED Light Fixture Project ­ FC1 Director's Conference Room: Life Cycle Cost and Break-even Analysis light fixtures in existing or new buildings across campus. Scope of Work On August 27, 2012, the six

Johnston, Daniel

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Bright three-band white light generated from CdSe/ZnSe quantum dot-assisted Sr{sub 3}SiO{sub 5}:Ce{sup 3+},Li{sup +}-based white light-emitting diode with high color rendering index  

SciTech Connect (OSTI)

In this study, bright three-band white light was generated from the CdSe/ZnSe quantum dot (QD)-assisted Sr{sub 3}SiO{sub 5}:Ce{sup 3+},Li{sup +}-based white light-emitting diode (WLED). The CdSe/ZnSe core/shell structure was confirmed by energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The CdSe/ZnSe QDs showed high quantum efficiency (79%) and contributed to the high luminous efficiency ({eta}{sub L}) of the fabricated WLED. The WLED showed bright natural white with excellent color rendering property ({eta}{sub L}=26.8 lm/W, color temperature=6140 K, and color rendering index=85) and high stability against the increase in forward bias currents from 20 to 70 mA.

Jang, Ho Seong; Kwon, Byoung-Hwa; Jeon, Duk Young [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Yang, Heesun [Department of Materials Science and Engineering, Hongik University, 72-1, Sangsu-dong, Mapo-gu, Seoul 121-791 (Korea, Republic of)

2009-10-19T23:59:59.000Z

322

LED Update  

SciTech Connect (OSTI)

This article, which will appear in RESIDENTIAL LIGHTING MAGAZINE, interviews PNNL's Kelly Gordon and presents the interview in question and answer format. The topic is a light emitting diode (LED) lighting also known as solid state lighting. Solid state lighting will be a new category in an energy efficient lighting fixture design competition called Lighting for Tomorrow sponsored by the US Department of Energy Emerging Technologies Office, the American Institute for Lighting, and the Consortium for Energy Efficiency. LED technology has been around since the ’60s, but it has been used mostly for indicator lights on electronics equipment. The big breakthrough was the development in the 1990s of blue LEDs which can be combined with the red and green LEDs that already existed to make white light. LEDs produce 25 to 40 lumens of light per watt of energy used, almost as much as a CFL (50 lumens per watt) and much more efficient than incandescent sources, which are around 15 lumens per watt. They are much longer lived and practical in harsh environments unsuitable for incandescent lighting. They are ready for niche applications now, like under-counter lighting and may be practical for additional applications as technological challenges are worked out and the technology is advancing in leaps and bounds.

Johnson, Mark L.; Gordon, Kelly L.

2006-09-01T23:59:59.000Z

323

Method of making organic light emitting devices  

DOE Patents [OSTI]

The present invention provides a method for the preparation of organic light-emitting devices comprising a bilayer structure made by forming a first film layer comprising an electroactive material and an INP precursor material, and exposing the first film layer to a radiation source under an inert atmosphere to generate an interpenetrating network polymer composition comprising the electroactive material. At least one additional layer is disposed on the reacted first film layer to complete the bilayer structure. The bilayer structure is comprised within an organic light-emitting device comprising standard features such as electrodes and optionally one or more additional layers serving as a bipolar emission layer, a hole injection layer, an electron injection layer, an electron transport layer, a hole transport layer, exciton-hole transporting layer, exciton-electron transporting layer, a hole transporting emission layer, or an electron transporting emission layer.

Shiang, Joseph John (Niskayuna, NY); Janora, Kevin Henry (Schenectady, NY); Parthasarathy, Gautam (Saratoga Springs, NY); Cella, James Anthony (Clifton Park, NY); Chichak, Kelly Scott (Clifton Park, NY)

2011-03-22T23:59:59.000Z

324

Numerical Modelling of Light Emission and Propagation in (Organic) LEDs with the Green's Tensor  

E-Print Network [OSTI]

light emitting diodes, light emission, light extraction, dipole radiation, stratified media, layered surpasses incandescent sources by a factor of 2 and with further improvements light emitting diodes could on light extraction techniques from inorganic light emitting diodes we recommend chapter 5 in 1 . Organic

Floreano, Dario

325

Off-grid energy services for the poor: Introducing LED lighting in the Millennium Villages Project in Malawi  

E-Print Network [OSTI]

) powered by batteries, which are in turn charged by grid electricity or small solar panels, have emerged 2009 Keywords: Solar Lighting Development a b s t r a c t Lanterns that use light-emitting diodes (LEDs as a cost-competitive alternative to kerosene and other fuel-based lighting technologies, offering brighter

Modi, Vijay

326

Light emitting device having peripheral emissive region  

DOE Patents [OSTI]

Light emitting devices are provided that include one or more OLEDs disposed only on a peripheral region of the substrate. An OLED may be disposed only on a peripheral region of a substantially transparent substrate and configured to emit light into the substrate. Another surface of the substrate may be roughened or include other features to outcouple light from the substrate. The edges of the substrate may be beveled and/or reflective. The area of the OLED(s) may be relatively small compared to the substrate surface area through which light is emitted from the device. One or more OLEDs also or alternatively may be disposed on an edge of the substrate about perpendicular to the surface of the substrate through which light is emitted, such that they emit light into the substrate. A mode expanding region may be included between each such OLED and the substrate.

Forrest, Stephen R

2013-05-28T23:59:59.000Z

327

Characterizing Ion Profiles in Dynamic Junction Light-Emitting...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

advantage in applications such as light-emitting devices, transistors, and electrochromic devices, among others. Evidence suggests that the profiles of ions and...

328

Green route synthesis of high quality CdSe quantum dots for applications in light emitting devices  

SciTech Connect (OSTI)

Investigation was made on light emitting diodes fabricated using CdSe quantum dots. CdSe quantum dots were synthesized chemically using olive oil as the capping agent, instead of toxic phosphine. Room temperature photoluminescence investigation showed sharp 1st excitonic emission peak at 568 nm. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting devices were fabricated by solution process. The electroluminescence study showed low turn on voltage ({approx}2.2 V) .The EL peak intensity was found to increase by increasing the operating current. - Graphical abstract: Light emitting diode was fabricated using CdSe quantum dots using olive oil as the capping agent, instead of toxic phosphine. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting device shows strong electroluminescence in the range 630-661 nm. Highlights: Black-Right-Pointing-Pointer CdSe Quantum dots were synthesized using olive oil as the capping agent. Black-Right-Pointing-Pointer Light emitting device was fabricated using CdSe QDs/P3HT polymer heterojunction. Black-Right-Pointing-Pointer The I-V characteristics study showed low turn on voltage at {approx}2.2 V. Black-Right-Pointing-Pointer The EL peak intensity increases with increasing the operating current.

Bera, Susnata, E-mail: susnata.bera@gmail.com [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Singh, Shashi B. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: physkr@phy.iitkgp.ernet.in [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

2012-05-15T23:59:59.000Z

329

Bright Light-Emitting Diodes based on Organometal Halide Perovskite  

E-Print Network [OSTI]

this class of materials to be excellent semiconductors for optoelectronic devices.1-7 Their primary advantages lie in the fact that they can be easily solution processed, require no high temperature heating, and they possess an optical bandgap which...

Tan, Zhi-Kuang; Moghaddam, Reza Saberi; Lai, May Ling; Docampo, Pablo; Higler, Ruben; Deschler, Felix; Price, Michael; Sadhanala, Aditya; Pazos, Luis M.; Credgington, Dan; Hanusch, Fabian; Bein, Thomas; Snaith, Henry J.; Friend, Richard H.

2014-08-03T23:59:59.000Z

330

Functional Polymer Architectures for Solution Processed Organic Light Emitting Diodes  

E-Print Network [OSTI]

through formation of the tetrazole from 4-bromobenzonitrile13 5-(4-Bromophenyl)tetrazole, 7 2-(4-tert- Butylphenyl)-5-(

Poulsen, Daniel Andrew

2010-01-01T23:59:59.000Z

331

Zinc Oxide and Nitride Nanowire Based Light Emitting Diodes  

E-Print Network [OSTI]

of incandescent light bulb, fluorescent lamp, and blue lightof incandescent light bulb, fluorescent lamp, and blue lightincandescent bulb and is on the same order as fluorescent

Lai, Elaine Michelle

2009-01-01T23:59:59.000Z

332

Zinc Oxide and Nitride Nanowire Based Light Emitting Diodes  

E-Print Network [OSTI]

only be able to find incandescent lightbulbs and fluorescent10: Output spectra of incandescent light bulb, fluorescentemission spectra. The incandescent light bulb for example

Lai, Elaine Michelle

2009-01-01T23:59:59.000Z

333

Energy Savings Estimates of Light Emitting Diodes in Niche Lighting...  

Office of Environmental Management (EM)

in Niche Lighting Applications Prepared for: Building Technologies Program Office of Energy Efficiency and Renewable Energy U.S. Department of Energy Prepared by: Navigant...

334

Nanobeam Photonic Crystal Cavity Light-Emitting Diodes  

E-Print Network [OSTI]

We present results on electrically driven nanobeam photonic crystal cavities formed out of a lateral p-i-n junction in gallium arsenide. Despite their small conducting dimensions, nanobeams have robust electrical properties with high current densities possible at low drive powers. Much like their two-dimensional counterparts, the nanobeam cavities exhibit bright electroluminescence at room temperature from embedded 1,250 nm InAs quantum dots. A small room temperature differential gain is observed in the cavities with minor beam self-heating suggesting that lasing is possible. These results open the door for efficient electrical control of active nanobeam cavities for diverse nanophotonic applications.

Shambat, Gary; Petykiewicz, Jan; Mayer, Marie A; Sarmiento, Tomas; Harris, James; Haller, Eugene E; Vuckovic, Jelena

2011-01-01T23:59:59.000Z

335

Energy Savings Estimates of Light Emitting Diodes | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Career Scientists'Montana.Program -Department oftoThese Web sitesEERECommercial2010EnergyThis report

336

Enhanced Light Extraction from Organic Light Emitting Diodes - Energy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing Zirconia NanoparticlesSmart

337

Light-Emitting Diodes on Semipolar Bulk Gallium Nitride Substrate |  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in3.pdfEnergy Health andofIanJenniferLeslie Pezzullo:

338

Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays  

SciTech Connect (OSTI)

Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville

2011-01-01T23:59:59.000Z

339

E-Print Network 3.0 - avalanche diode array Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diodes 5. The inductance, La... Improved Light Output of Photonic Crystal Light Emitting Diode Fabricated by Anodized Aluminum Oxide Nano... -patterns , , ( ), , ( ) 16:30...

340

An LED pulser for measuring photomultiplier linearity  

E-Print Network [OSTI]

A light-emitting diode (LED) pulser for testing the low-rate response of a photomultiplier tube (PMT) to scintillator-like pulses has been designed, developed, and implemented. This pulser is intended to simulate 80 ns full width at half maximum photon pulses over the dynamic range of the PMT, in order to precisely determine PMT linearity. This particular design has the advantage that, unlike many LED test rigs, it does not require the use of multiple calibrated LEDs, making it insensitive to LED gain drifts. Instead, a finite-difference measurement is made using two LEDs which need not be calibrated with respect to one another. These measurements give a better than 1% mapping of the response function, allowing for the testing and development of particularly linear PMT bases.

Friend, M; Quinn, B

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

High Performance Green LEDs by Homoepitaxial  

SciTech Connect (OSTI)

This work's objective was the development of processes to double or triple the light output power from green and deep green (525 - 555 nm) AlGaInN light emitting diode (LED) dies within 3 years in reference to the Lumileds Luxeon II. The project paid particular effort to all aspects of the internal generation efficiency of light. LEDs in this spectral region show the highest potential for significant performance boosts and enable the realization of phosphor-free white LEDs comprised by red-green-blue LED modules. Such modules will perform at and outperform the efficacy target projections for white-light LED systems in the Department of Energy's accelerated roadmap of the SSL initiative.

Wetzel, Christian; Schubert, E Fred

2009-11-22T23:59:59.000Z

342

An LED-based Flasher System for VERITAS  

E-Print Network [OSTI]

We describe a flasher system designed for use in monitoring the gains of the photomultiplier tubes used in the VERITAS gamma-ray telescopes. This system uses blue light-emitting diodes (LEDs) so it can be operated at much higher rates than a traditional laser-based system. Calibration information can be obtained with better statistical precision with reduced loss of observing time. The LEDs are also much less expensive than a laser. The design features of the new system are presented, along with measurements made with a prototype mounted on one of the VERITAS telescopes.

Hanna, D; McCutcheon, M; Nikkinen, L; 10.1016/j.nima.2009.10.107

2009-01-01T23:59:59.000Z

343

138 JOURNAL OF DISPLAY TECHNOLOGY, VOL. 2, NO. 2, JUNE 2006 Improving the Performance of Organic Light-Emitting  

E-Print Network [OSTI]

­LiF­Al is believed to be due to the enhancement of elec- tron injection by thermal treatment. Secondary ion mass spec Light-Emitting Diodes Containing BCP/LiF/Al by Thermal Annealing J. X. Sun, Student Member, IEEE, X. L. However, other devices consisting of Alq3 LiF/Al were less affected. It is believed that the thermal

344

Organic LEDs for optoelectronic neural networks  

E-Print Network [OSTI]

In this thesis, I investigate the characteristics of Organic Light Emitting Diodes (OLEDs) and assess their suitability for use in the Compact Optoelectronic Integrated Neural (COIN) coprocessor. The COIN coprocessor, a ...

Mars, Risha R

2012-01-01T23:59:59.000Z

345

Light emitting ceramic device and method for fabricating the same  

DOE Patents [OSTI]

A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, and alternative methods of fabrication for the same are claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

Valentine, Paul; Edwards, Doreen D.; Walker Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

2004-11-30T23:59:59.000Z

346

2010 Minerals Yearbook U.S. Department of the Interior  

E-Print Network [OSTI]

circuits (ICs) and optoelectronic devices [laser diodes, light-emitting diodes (LEDs), photodetectors

347

Concave-hemisphere-patterned organic top-light emitting device  

DOE Patents [OSTI]

A first device is provided. The first device includes an organic light emitting device, which further comprises a first electrode, a second electrode, and an organic emissive layer disposed between the first and second electrode. Preferably, the second electrode is more transparent than the first electrode. The organic emissive layer has a first portion shaped to form an indentation in the direction of the first electrode, and a second portion shaped to form a protrusion in the direction of the second electrode. The first device may include a plurality of organic light emitting devices. The indentation may have a shape that is formed from a partial sphere, a partial cylinder, a pyramid, or a pyramid with a mesa, among others. The protrusions may be formed between adjoining indentations or between an indentation and a surface parallel to the substrate.

Forrest, Stephen R; Slootsky, Michael; Lunt, Richard

2014-01-21T23:59:59.000Z

348

Organic light emitting device having multiple separate emissive layers  

DOE Patents [OSTI]

An organic light emitting device having multiple separate emissive layers is provided. Each emissive layer may define an exciton formation region, allowing exciton formation to occur across the entire emissive region. By aligning the energy levels of each emissive layer with the adjacent emissive layers, exciton formation in each layer may be improved. Devices incorporating multiple emissive layers with multiple exciton formation regions may exhibit improved performance, including internal quantum efficiencies of up to 100%.

Forrest, Stephen R. (Ann Arbor, MI)

2012-03-27T23:59:59.000Z

349

Organic light emitting device structure for obtaining chromaticity stability  

DOE Patents [OSTI]

The present invention relates to organic light emitting devices (OLEDs). The devices of the present invention are efficient white or multicolored phosphorescent OLEDs which have a high color stability over a wide range of luminances. The devices of the present invention comprise an emissive region having at least two emissive layers, with each emissive layer comprising a different host and emissive dopant, wherein at least one of the emissive dopants emits by phosphorescence.

Tung, Yeh-Jiun (Princeton, NJ); Ngo, Tan (Levittown, PA)

2007-05-01T23:59:59.000Z

350

Multicolor, High Efficiency, Nanotextured LEDs  

SciTech Connect (OSTI)

We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and green for Solid State Lighting applications. Accomplishments in the duration of the contract period include (i) heteroepitaxy of nitrogen-polar LEDs on sapphire, (ii) heteroepitaxy of semipolar (11{bar 2}2) green LEDs on sapphire, (iii) synthesis of quantum-dot loaded nanoporous GaN that emits white light without phosphor conversion, (iv) demonstration of the highest quality semipolar (11{bar 2}2) GaN on sapphire using orientation-controlled epitaxy, (v) synthesis of nanoscale GaN and InGaN medium, and (vi) development of a novel liftoff process for manufacturing GaN thin-film vertical LEDs. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

Jung Han; Arto Nurmikko

2011-09-30T23:59:59.000Z

351

Efficient bottom cathodes for organic light-emitting devices  

SciTech Connect (OSTI)

Bilayers of aluminum and an alkali fluoride are well-known top cathode contacts for organic light-emitting devices but have never been successfully applied as bottom contacts. We describe a bilayer bottom cathode contact for organic electronic devices based on reversing the well-known top cathode structure such that the aluminum, rather than the alkali fluoride, contacts the organic material. Electron-only devices were fabricated showing enhanced electron injection from this bottom contact. Kelvin probe, x-ray photoelectron spectroscopy experiments, and thermodynamic calculations suggest that the enhancement results from n doping of the organic material by dissociated alkali metals.

Liu Jie; Duggal, Anil R.; Shiang, Joseph J.; Heller, Christian M. [General Electric Global Research, 1 Research Circle, Niskayuna, New York 12309 (United States)

2004-08-02T23:59:59.000Z

352

The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells  

SciTech Connect (OSTI)

Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2?-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy){sub 2}(pbpy)][PF{sub 6}]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage.

Meier, Sebastian B., E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Hartmann, David; Sarfert, Wiebke, E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Winnacker, Albrecht [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany)

2014-09-14T23:59:59.000Z

353

Tests gauge LED sensors for fuel-dye measurements  

SciTech Connect (OSTI)

The goal of this work was to develop a low cost, robust sensor to allow direct measurement of Solvent Red 164 dye concentration in off-road fuel at refineries and fuel terminals. Optical absorption sensors based on light emitting diodes (LEDs) are rugged, low-cost, have low power consumption, and can be designed to be intrinsically safe.LED-based systems have been used in a variety of chemical detection applications including heavy metals, pH, CO2, and O2. The approach for this work was to develop a sensor that could be mounted on a pipeline sight glass, precluding the need for direct contact of the sensor with the fuel. Below is described the design and testing of three different LED/photodiode sensors utilizing reflectance spectrometry for the measurement of dye concentration.

Ozanich, Richard M.; Lucke, Richard B.; Melville, Angela M.; Wright, Bob W.

2009-10-19T23:59:59.000Z

354

Microsoft PowerPoint - Ghisla - Snap Circuits for 4th and 6th...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

because of the diode. The diode in the snap circuit box looks like this: LED (Light Emitting Diode) LED symbol: A LED (Light Emitting Diode) is a diode that emits light while...

355

All inorganic colloidal quantum dot LEDs  

E-Print Network [OSTI]

This thesis presents the first colloidal quantum dot light emitting devices (QD-LEDs) with metal oxide charge transport layers. Colloidally synthesized quantum dots (QDs) have shown promise as the active material in ...

Wood, Vanessa Claire

2007-01-01T23:59:59.000Z

356

Development of ZnO Based Light Emitting Diodes and Laser Diodes  

E-Print Network [OSTI]

TO5 cans using conductive epoxy resin and annealed at 150 oonto TO5 can using conductive epoxy resin. Figure 4.4 Device

Kong, Jieying

2012-01-01T23:59:59.000Z

357

Ultra-thin ohmic contacts for p-type nitride light emitting devices  

DOE Patents [OSTI]

A flip-chip semiconductor based Light Emitting Device (LED) can include an n-type semiconductor substrate and an n-type GaN epi-layer on the substrate. A p-type GaN epi-layer can be on the n-type GaN epi-layer and a metal ohmic contact p-electrode can be on the p-type GaN epi-layer, where the metal ohmic contact p-electrode can have an average thickness less than about 25 .ANG.. A reflector can be on the metal ohmic contact p-electrode and a metal stack can be on the reflector. An n-electrode can be on the substrate opposite the n-type GaN epi-layer and a bonding pad can be on the n-electrode.

Raffetto, Mark; Bharathan, Jayesh; Haberern, Kevin; Bergmann, Michael; Emerson, David; Ibbetson, James; Li, Ting

2014-06-24T23:59:59.000Z

358

Oxycarbonitride phosphors and light emitting devices using the same  

DOE Patents [OSTI]

Disclosed herein is a novel family of oxycarbidonitride phosphor compositions and light emitting devices incorporating the same. Within the sextant system of M--Al--Si--O--N--C--Ln and quintuplet system of M--Si--O--N--C--Ln (M=alkaline earth element, Ln=rare earth element), the phosphors are composed of either one single crystalline phase or two crystalline phases with high chemical and thermal stability. In certain embodiments, the disclosed phosphor of silicon oxycarbidonitrides emits green light at wavelength between 530-550 nm. In further embodiments, the disclosed phosphor compositions emit blue-green to yellow light in a wavelength range of 450-650 nm under near-UV and blue light excitation.

Li, Yuanqiang; Romanelli, Michael Dennis; Tian, Yongchi

2013-10-08T23:59:59.000Z

359

Oxycarbonitride phosphors and light emitting devices using the same  

DOE Patents [OSTI]

Disclosed herein is a novel family of oxycarbonitride phosphor compositions and light emitting devices incorporating the same. Within the sextant system of M--Al--Si--O--N--C--Ln and quintuplet system of M--Si--O--N--C--Ln (M=alkaline earth element, Ln=rare earth element), the phosphors are composed of either one single crystalline phase or two crystalline phases with high chemical and thermal stability. In certain embodiments, the disclosed phosphor of silicon oxycarbonitrides emits green light at wavelength between 530-550 nm. In further embodiments, the disclosed phosphor compositions emit blue-green to yellow light in a wavelength range of 450-650 nm under near-UV and blue light excitation.

Li, Yuanqiang; Romanelli, Michael Dennis; Tian, Yongchi

2014-07-08T23:59:59.000Z

360

Proceedings of the 37th ASME Mechanisms & Robotics Conference August 4-7 2013, Portland, Oregon, USA  

E-Print Network [OSTI]

objects that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes functions such as light and sound performance. In addition, conductivity, LED (Light Emitting Diodes) output

Demaine, Erik

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices  

E-Print Network [OSTI]

that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes functions such as light and sound performance. In addition, conductivity, LED (Light Emitting Diodes) output

Demaine, Erik

362

anhydride cured dgeba: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of dental composites cured with blue light emitting diodes with either a light emitting diode (LED) based light curing unit (LCU) or a conventional halogen LCU do reserved....

363

E-Print Network 3.0 - amorphous polymer field-effect Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Engineering ; Materials Science 60 Patterning-free integration of polymer light-emitting diode and polymer transistor Summary: contains a light-emitting diode LED driven by a...

364

Apply: Solid-State Lighting Advanced Technology R&D - 2014(DE...  

Energy Savers [EERE]

Through research and development of solid-state lighting (SSL),including both light-emitting diode (LED) and organic light emitting diode (OLED) technologies, the objectives of...

365

Optoelectronic devices based on electrically tunable p–n diodes in a monolayer dichalcogenide  

E-Print Network [OSTI]

The p–n junction is the functional element of many electronic and optoelectronic devices, including diodes, bipolar transistors, photodetectors, light-emitting diodes and solar cells. In conventional p–n junctions, the ...

Baugher, Britton W. H.

366

Excitation mechanisms in dye-doped organic light-emitting devices F. Pschenitzkaa)  

E-Print Network [OSTI]

Excitation mechanisms in dye-doped organic light-emitting devices F. Pschenitzkaa) and J. C. Sturmb In an organic light-emitting device with a polymeric matrix concurrently doped with two different dyes, the photoluminescence PL and electroluminescence EL spectra are observed to be very different, with both dyes emitting

367

Tunable White-Light-Emitting Mn-Doped ZnSe Nanocrystals Vijay Kumar Sharma,  

E-Print Network [OSTI]

Tunable White-Light-Emitting Mn-Doped ZnSe Nanocrystals Vijay Kumar Sharma, Burak Guzelturk, Talha report white-light-emitting Mn-doped ZnSe nanocrystals (NCs) that are synthesized using modified orange emission (580 nm), allowed us to achieve excitation wavelength tailorable white-light generation

Demir, Hilmi Volkan

368

DEPARTMENT OF CHEMICAL ENGINEERING DEPARTMENT OF MECHANICAL AND INDUSTRIAL ENGINEERING  

E-Print Network [OSTI]

-oxide-semiconductor field effect transistor (MOSFET) o Light emitting diodes (LEDs): principles and characteristics o

Massachusetts at Amherst, University of

369

A Genetic Algorithm Method for Multi-spot Diffuse Infrared Wireless Communications  

E-Print Network [OSTI]

optoelectronic devices, such as light emitting diodes (LEDs) and silicon detectors [2]. However there are two

Haddadi, Hamed

370

Transport Equations for Semiconductors Prof. Dr. Ansgar Jungel  

E-Print Network [OSTI]

- cations have been invented; for instance, semiconductor lasers, solar cells, light-emitting diodes (LED

Jüngel, Ansgar

371

Nottingham Trent University, PhD Studentship Opportunities in Art and Design, October 2014 Research Group: Supervisor  

E-Print Network [OSTI]

incorporating light-emitting diode (LED) chips. However, the group now plans to develop an automated

Evans, Paul

372

Probabilistic Phase Unwrapping for Time-of-Flight Cameras David Droeschel, Dirk Holz and Sven Behnke  

E-Print Network [OSTI]

. They employ an array of light emitting diodes (LEDs) that illuminate the environment with modulated near

Behnke, Sven

373

Scavenger Hunt 2012 Answer Key Thank you for attending this year's Engineering Discovery Days and for taking part in our Scavenger Hunt! We hope you enjoyed  

E-Print Network [OSTI]

?.................................The hottest: resistors. The Brightest: LED's (Light Emitting Diodes) 6) How does an airplane fly without

Anderson, Richard

374

Agronomy Journal Volume 105, Issue 6 2013 1769 Crop Economics, Production & Management  

E-Print Network [OSTI]

include light emitting diodes, LEDs (Ryu et al., 2010), radiometers (Eklundh et al., 2011), and digital

Gitelson, Anatoly

375

Metameric Modulation for Diffuse Visible Light Communications with Constant Ambient Lighting  

E-Print Network [OSTI]

untapped for wireless communications. Advancements in light emitting diode (LED) technology are making

Little, Thomas

376

Table Set-up with Materials Target Audience: Parents of elementary school students (grades 3-6) and Middle and High School Students  

E-Print Network [OSTI]

students. BOM: LED (Light Emitting Diode), breadboard, resistor, Wires, 9V battery, Potentiometer to manage

Linhardt, Robert J.

377

A-1 1999 SITE ENVIRONMENTAL REPORT APPENDIX A: GLOSSARY  

E-Print Network [OSTI]

Organization LED Light Emitting Diode LIE Long Island Expressway LINAC Linear accelerator MACT Maximum

378

DOCTORAL CANDIDATE: Raju Shrestha DEGREE: Philosophiae Doctor (PhD)  

E-Print Network [OSTI]

and technologies: multi- camera (MCMSI), filter array (FAMSI), and LED (Light Emitting Diode) illumination (LEDMSI

Løw, Erik

379

Power Quality Improvements in Lighting Systems Mr. Ashish Shrivastava  

E-Print Network [OSTI]

from early incandescent lamps to present generation light emitting diodes (LEDs). Incandescent light

Kumar, M. Jagadesh

380

LEDs for Energy Efficient Greenhouse Lighting  

E-Print Network [OSTI]

Light energy is an important factor for plant growth. In regions where the natural light source, i.e. solar radiation, is not sufficient for growth optimization, additional light sources are being used. Traditional light sources such as high pressure sodium lamps and other metal halide lamps are not very efficient and generate high radiant heat. Therefore, new sustainable solutions should be developed for energy efficient greenhouse lighting. Recent developments in the field of light source technologies have opened up new perspectives for sustainable and highly efficient light sources in the form of light-emitting diodes, i.e. LEDs, for greenhouse lighting. This review focuses on the potential of LEDs to replace traditional light sources in the greenhouse. In a comparative economic analysis of traditional vs. LED lighting, we show that the introduction of LEDs allows reduction of the production cost of vegetables in the long-run of several years, due to the high energy efficiency, low maintenance cost and lon...

Singh, Devesh; Meinhardt-Wollweber, Merve; Roth, Bernhard

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Wide-Area Thermal Processing of Light-Emitting Materials  

SciTech Connect (OSTI)

Silicon carbide based materials and devices have been successfully exploited for diverse electronic applications. However, they have not achieved the same success as Si technologies due to higher material cost and higher processing temperatures required for device development. Traditionally, SiC is not considered for optoelectronic applications because it has an indirect bandgap. However, AppliCote Associates, LLC has developed a laser-based doping process which enables light emission in SiC through the creation of embedded p-n junctions. AppliCote laser irradiation of silicon carbide allows two different interaction mechanisms: (1) Laser conversion or induced phase transformation which creates carbon rich regions that have conductive properties. These conductive regions are required for interconnection to the light emitting semiconducting region. (2) Laser doping which injects external dopant atoms into the substrate that introduces deep level transition states that emit light when electrically excited. The current collaboration with AppliCote has focused on the evaluation of ORNL's unique Pulse Thermal Processing (PTP) technique as a replacement for laser processing. Compared to laser processing, Pulse Thermal Processing can deliver similar energy intensities (20-50 kW/cm2) over a much larger area (up to 1,000 cm2) at a lower cost and much higher throughput. The main findings of our investigation; which are significant for the realization of SiC based optoelectronic devices, are as follows: (1) The PTP technique is effective in low thermal budget activation of dopants in SiC similar to the laser technique. The surface electrical conductivity of the SiC samples improved by about three orders of magnitude as a result of PTP processing which is significant for charge injection in the devices; (2) The surface composition of the SiC film can be modified by the PTP technique to create a carbon-rich surface (increased local C:Si ratio from 1:1 to 2.9:1). This is significant as higher thermal and electrical conductivities of the surface layer are critical for a successful development of integrated optoelectronic devices; and (3) PTP provides low thermal budget dopant activation with a controlled depth profile, which can be exploited for high performance device development with selective patterning of the substrate. This project has successfully demonstrated that a low thermal budget annealing technique, such as PTP, is critical to defining the path for low cost electronic devices integrated on glass or polymeric substrates. This project is complimentary to the goals of the Solid State Lighting Program within DOE. It involves new manufacturing techniques for light emitting materials that are potentially much lower cost and energy efficient than existing products. Significant opportunity exists for further exploration of AppliCote's material and device technology in combination with ORNL's PTP technique, modeling, and characterization capabilities.

Duty, C.; Quick, N. (AppliCote Associates, LLC) [AppliCote Associates, LLC

2011-09-30T23:59:59.000Z

382

Carbonitride based phosphors and light emitting devices using the same  

DOE Patents [OSTI]

Disclosed herein is a novel group of carbidonitride phosphors and light emitting devices which utilize these phosphors. In certain embodiments, the present invention is directed to a novel family of carbidonitride-based phosphors expressed as follows: Ca.sub.1-xAl.sub.x-xySi.sub.1-x+xyN.sub.2-x-xyC.sub.xy:A; (1) Ca.sub.1-x-zNa.sub.zM(III).sub.x-xy-zSi.sub.1-x+xy+zN.sub.2-x-xyC.sub.xy:- A; (2) M(II).sub.1-x-zM(I).sub.zM(III).sub.x-xy-zSi.sub.1-x+xy+zN.sub.2-x- -xyC.sub.xy:A; (3) M(II).sub.1-x-zM(I).sub.zM(III).sub.x-xy-zSi.sub.1-x+xy+zN.sub.2-x-xy-2w/- 3C.sub.xyO.sub.w-v/2H.sub.v:A; and (4) M(II).sub.1-x-zM(I).sub.zM(III).sub.x-xy-zSi.sub.1-x+xy+zN.sub.2-x-xy-2w/- 3-v/3C.sub.xyO.sub.wH.sub.v:A, (4a) wherein 0xy+z, and 0

Li, Yuanqiang; Tian, Yongchi; Romanelli, Michael Dennis

2013-08-20T23:59:59.000Z

383

Enhancing the efficiency of organic LEDs through spin-orbit coupling of charge-transfer states  

E-Print Network [OSTI]

In this thesis, the possibility of enhancing the efficiency of small molecule organic light-emitting diodes through spin-orbit effects is examined. Because only singlet spin states, statistically one quarter of the total ...

Rivoire, Kelley (Kelley E.)

2006-01-01T23:59:59.000Z

384

Mechanical Engineering Department 04 November 2013  

E-Print Network [OSTI]

Department Light Sources Light emitting diode (LED) When a light-emitting diode is forward biased (switched a p-n junction #12;Mechanical Engineering Department Light Sources Light emitting diode (LED the p-n junction #12;Mechanical Engineering Department Light Sources Light emitting diode (LED) #12

Furlong, Cosme

385

Characterization of failure modes in deep UV and deep green LEDs utilizing advanced semiconductor localization techniques.  

SciTech Connect (OSTI)

We present the results of a two-year early career LDRD that focused on defect localization in deep green and deep ultraviolet (UV) light-emitting diodes (LEDs). We describe the laser-based techniques (TIVA/LIVA) used to localize the defects and interpret data acquired. We also describe a defect screening method based on a quick electrical measurement to determine whether defects should be present in the LEDs. We then describe the stress conditions that caused the devices to fail and how the TIVA/LIVA techniques were used to monitor the defect signals as the devices degraded and failed. We also describe the correlation between the initial defects and final degraded or failed state of the devices. Finally we show characterization results of the devices in the failed conditions and present preliminary theories as to why the devices failed for both the InGaN (green) and AlGaN (UV) LEDs.

Tangyunyong, Paiboon; Miller, Mary A.; Cole, Edward Isaac, Jr.

2012-03-01T23:59:59.000Z

386

LED-Induced Fluorescence System for Tea Classification and Quality Assessment  

E-Print Network [OSTI]

A fluorescence system is developed by using several light emitting diodes (LEDs) with different wavelengths as excitation light sources. The fluorescence detection head consists of multi LED light sources and a multimode fiber for fluorescence collection, where the LEDs and the corresponding filters can be easily chosen to get appropriate excitation wavelengths for different applications. By analyzing fluorescence spectra with the principal component analysis method, the system is utilized in the classification of four types of green tea beverages and two types of black tea beverages. Qualities of the Xihu Longjing tea leaves of different grades, as well as the corresponding liquid tea samples, are studied to further investigate the ability and application of the system in the evaluation of classification/quality of tea and other foods.

Dong, Yongjiang; Mei, Liang; Feng, Chao; Yan, Chunsheng; He, Sailing

2013-01-01T23:59:59.000Z

387

Aspects of charge recombination and charge transport in organic solar cells and light-emitting devices  

E-Print Network [OSTI]

In this thesis, aspects of charge reconbination and charge transport in organic solar cells and light-emitting devices are presented. These devices show promise relative to traditional inorganic semiconductors. We show ...

Difley, Seth

2010-01-01T23:59:59.000Z

388

Long-term Testing Results for the 2008 Installation of LED Luminaires at the I-35 West Bridge in Minneapolis  

SciTech Connect (OSTI)

This document reports the long-term testing results from an extended GATEWAY project that was first reported in “Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting at the I-35W Bridge, in Minneapolis, MN,” August 2009. That original report presented the results of lighting the newly reconstructed I 35W Bridge using LEDs in place of conventional high-pressure sodium (HPS) roadway luminaires, comparing energy use and illuminance levels with a simulated baseline condition. That installation was an early stage implementation of LED lighting and remains one of the oldest installations in continued operation today. This document provides an update of the LED system’s performance since its installation in September 2008.

Kinzey, Bruce R.; Davis, Robert G.

2014-09-30T23:59:59.000Z

389

2011 Minerals Yearbook U.S. Department of the Interior  

E-Print Network [OSTI]

Cs) and optoelectronic devices [laser diodes, light-emitting diodes (lEDs), photodetectors, and solar cells]. Gallium

390

Light source comprising a common substrate, a first led device and a second led device  

DOE Patents [OSTI]

At least one stacked organic or polymeric light emitting diode (PLEDs) devices to comprise a light source is disclosed. At least one of the PLEDs includes a patterned cathode which has regions which transmit light. The patterned cathodes enable light emission from the PLEDs to combine together. The light source may be top or bottom emitting or both.

Choong, Vi-En (Carlsbad, CA)

2010-02-23T23:59:59.000Z

391

LED Chips and Packaging for 120 LPW SSL Component  

SciTech Connect (OSTI)

Cree has developed a new, high-efficiency, low-cost, light emitting diode (LED) lamp module that should be capable of replacing standard, halogen, fluorescent and metal halide lamps based on the total cost of ownership. White LEDs are produced by combining one or more saturated color LEDs with a phosphor or other light down-converting media to achieve white broad-band illumination. This two year project addressed LED chip and package efficiency improvements to establish a technology platform suitable for low-cost, high-efficiency commercial luminaires. Novel photonic-crystal LEDs were developed to improve the light extraction efficiency of blue GaN-based LEDs compared to the baseline technology. Improved packaging designs that reduced down-conversion and absorption related light losses, led to a higher overall LED efficiency. Specifically, blue LEDs were demonstrated with light output nearing 600 mW and an external quantum efficiency greater than 60 percent (using 1 mm2 chips at an operating current of 350 mA). The results were achieved using a novel, production capable photonic-crystal LED fabrication process. These LEDs formed the basis for a multi-chip white lamp module prototype, which provided 510 lumens light output at a correlated color temperature (CCT) of 3875 K and an operating current of 350 mA per 1mm2 chip. The overall conversion efficiency at 4100 K improved to ~ 65%. The resulting efficacy is 112 lumens per watt (LPW) â?? a 33% improvement over the start of the project. In addition, a proof-of-concept luminaire was demonstrated that provided a flux of 1700 lumens at a 3842 K CCT.

James Ibbetson

2009-09-30T23:59:59.000Z

392

Design and modelling of novel waveguide and light-emitting-diode-based photoreactors.  

E-Print Network [OSTI]

??In this dissertation, investigations on a range of photocatalytic reactors based on waveguides (optical fibres and quartz tubes) are presented. A study on a coupled… (more)

Denny, Frans

2010-01-01T23:59:59.000Z

393

Extremely Efficient Indium-Tin-Oxide-Free Green Phosphorescent Organic Light-Emitting Diodes  

SciTech Connect (OSTI)

This paper demonstrates extremely efficient (?P,max = 118 lm W?1) ITO-free green phosphorescent OLEDs (PHOLEDs) with multilayered, highly conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) films as the anode. The efficiency is obtained without any outcoupling-enhancing structures and is 44% higher than the 82 lm W?1 of similar optimized ITO-anode PHOLEDs. Detailed simulations show that this improvement is due largely to the intrinsically enhanced outcoupling that results from a weak microcavity effect.

Cai, Min; Ye, Zhuo; Xiao, Teng; Liu, Rui; Chen, Ying; Mayer, Robert W.; Biswas, Rana; Ho, Kai-Ming; Shinar, Ruth; Shinar, Joseph

2012-07-12T23:59:59.000Z

394

Electrical and Optical Enhancement in Internally Nanopatterned Organic Light-Emitting Diodes  

E-Print Network [OSTI]

Kao, K.C. , Hwang, W. Electrical Transport in Solids: withPress, 2009. Stallinga, P. Electrical Characterization offrom electrical model . 100

Fina, Michael Dane

2012-01-01T23:59:59.000Z

395

Fabrication of color tunable organic light-emitting diodes by an alignment free mask patterning method  

E-Print Network [OSTI]

that of the incandescent bulb and comparable with that of the fluorescent tube. OLEDs are a true sur- face/area lighting

396

Electrical and Optical Enhancement in Internally Nanopatterned Organic Light-Emitting Diodes  

E-Print Network [OSTI]

incandescent bulbs and fluorescent bulbs). Solid-stateindex (CRI) than fluorescent bulbs. Common examples where

Fina, Michael Dane

2012-01-01T23:59:59.000Z

397

Room temperature all-silicon photonic crystal nanocavity light emitting diode at sub-bandgap wavelengths  

E-Print Network [OSTI]

Silicon is now firmly established as a high performance photonic material. Its only weakness is the lack of a native electrically driven light emitter that operates CW at room temperature, exhibits a narrow linewidth in the technologically important 1300- 1600 nm wavelength window, is small and operates with low power consumption. Here, an electrically pumped all-silicon nano light source around 1300-1600 nm range is demonstrated at room temperature. Using hydrogen plasma treatment, nano-scale optically active defects are introduced into silicon, which then feed the photonic crystal nanocavity to enahnce the electrically driven emission in a device via Purcell effect. A narrow ({\\Delta}{\\lambda} = 0.5 nm) emission line at 1515 nm wavelength with a power density of 0.4 mW/cm2 is observed, which represents the highest spectral power density ever reported from any silicon emitter. A number of possible improvements are also discussed, that make this scheme a very promising light source for optical interconnects a...

Shakoor, A; Cardile, P; Portalupi, S L; Gerace, D; Welna, K; Boninelli, S; Franzo, G; Priolo, F; Krauss, T F; Galli, M; Faolain, L O

2013-01-01T23:59:59.000Z

398

Light-emitting diodes from polyfluorenes: characterisation and stability of performance  

E-Print Network [OSTI]

in my work. In the lab, I am indebted to Ji Seon and Peter for their generous advice, and Neil, Jim, Dickon and Steve for their frequent insights. Catherine, Kieran, Lukas and Mike have shared the ups and downs of the Ph.D. road from day one... deserve a special mention. No Ph.D. student can thrive without email and beer, and I am indebted to my friends for their dedicated support in those two activities – in no particular order: Andy, Carl, Martin, Sarah, Sharon, Simon, Stu, Spod, Svetty...

Seeley, Alexander J. A. B.

399

Organic light-emitting diodes using open-shell molecule as emitter: the emission from doublet  

E-Print Network [OSTI]

We fabricate OLEDs using a stable neutral {\\pi} radical, BDPA, as the emitter. There is only one electron in the singly occupied molecular orbital (SOMO) of this open-shell molecule. This feature makes the excited state of open-shell molecules be neither singlet nor triplet, but doublet. The key issue of how to harvest the triplet energy in an OLED is thus bypassed, due to the radiative decay of doublet is totally spin allowed. In the BDPA-based OLED, the emission was confirmed to be from the electronic transition from LUMO to SOMO, via the frontier molecular orbital analysis combined with the spectroscopy measurements. The maximum luminance of the OLEDs is 4879 cd/m2 which is comparable to the first reported Fluorescence-, Phosphorecence- and TADF-based OLEDs.

Peng, Qiming; Chen, Youchun; He, Chuanyou; Obolda, Ablikim; Li, Feng

2014-01-01T23:59:59.000Z

400

Comparing directed efficiency of III-nitride nanowire light-emitting diodes  

E-Print Network [OSTI]

III-nitride-based nanowires are a promising platform for solid-state lighting. III-nitride nanowires that act as natural waveguides to enhance directed extraction have previously been shown to be free of extended defects ...

Gradecak, Silvija

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Improvement of output coupling efficiency of organic light-emitting diodes by backside substrate modification  

E-Print Network [OSTI]

modification C. F. Madigan, M.-H. Lu, and J. C. Sturma) Center for Photonics and Optoelectronic Materials, Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 Received 8 November and at least triple it when high-index plastic substrates are used. The work is accompa- nied by modeling

402

Low-voltage polariton electroluminescence from an ultrastrongly coupled organic light-emitting diode  

SciTech Connect (OSTI)

We demonstrate electroluminescence from Frenkel molecular excitons ultrastrongly coupled to photons of a metal-clad microcavity containing a 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorene emissive layer. Thin layers of molybdenum oxide and 4,7-diphenyl-1,10-phenanthroline are used as hole and electron injection layers, respectively. The fabricated devices exhibit an electroluminescence threshold of 3.1?V, a value that is below the bare exciton energy. This result is found to be independent of detuning and consistent with a two-step process for polariton formation. Moreover, we investigate the quantum efficiency of carrier to polariton to photon conversion and obtain an external quantum efficiency of 0.1% for the fabricated structures, an improvement of 5 orders of magnitude over previous reports.

Gubbin, Christopher R.; Maier, Stefan A. [Experimental Solid State Group, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Kéna-Cohen, Stéphane, E-mail: s.kena-cohen@polymtl.ca [Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Quebec H3C 3A7 (Canada)

2014-06-09T23:59:59.000Z

403

2014-05-16 Issuance: Test Procedures for Integrated Light-Emitting Diode  

Energy Savers [EERE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustionImprovement3 Beryllium-Associated Worker2014 HouseCovered ConsumerProcedures forAvailability

404

SciTech Connect: "light emitting diode"  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systems controller systemsisSchedulesenriched uranium" Find +highlight

405

SciTech Connect: "light emitting diodes"  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systems controller systemsisSchedulesenriched uranium" Find

406

SciTech Connect: Demonstration Assessment of Light-Emitting Diode Parking  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systems controllerAdditiveBetatronAerogel Deep Bed

407

Colloidal Quantum Dot Light-Emitting Diodes Employing Phosphorescent Small Organic Molecules as Efficient Exciton  

E-Print Network [OSTI]

engineer, the potential energy transfer pumping scheme. Only Zhang et al. reported an enhancement enhancement factor in the external quantum efficiency over the conventional QLED structure, in which energy as Efficient Exciton Harvesters Evren Mutlugun,,,§, Burak Guzelturk,,§, Agus Putu Abiyasa,§, Yuan Gao,§ Xiao

Demir, Hilmi Volkan

408

Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: TopEnergyIDIQBusinessinSupporting Jobs and Diversifying

409

High-Efficiency and Stable White Organic Light-Emitting Diode Using a  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in3.pdfEnergy Health and Productivity QuestionnaireSingle Emitter | Department of

410

Understanding Drooping Light Emitting Diodes CEEM | U.S. DOE Office of  

Office of Science (SC) Website

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched5 IndustrialIsadoreConnecticutPhotos of AECSign Up for(SC)Office ofScience

411

Low-Cost Light-Emitting Diode Luminaire for General Illumination |  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in3.pdfEnergy Health andofIanJenniferLeslieEnergy LoanOfficialLow-Cost

412

Studies of solution-processed organic light-emitting diodes and their materials  

SciTech Connect (OSTI)

A hitherto unexplored approach is presented in which a small molecule is used as a host to polymer guests in solution-processed OLEDs. We find that the small molecule host results in much more efficient devices than the often-used alternative polymer host when used for the guests presented. It is likely that nano- and microstructural differences between the hosts contribute to the improvements, which highlights some interesting characteristics that can help to better understand the nature of these mixtures. A number of the guests used in this study were newly synthesized benzobisoxazole-based copolymers. New organic copolymers are presented that are based on the chemical structure of benzobisoxazoles, which have been shown in the past to have good electron transporting properties. The novel concept in this publication pertains to a change in the direction of polymerization, also known as the conjugation pathway, which we show increases the emission efficiency. This work highlights a unique and useful property of organic semiconducting materials in that they can be synthesized to create the desired characteristics. Earlier work is described that kick-started in our research group the use of small molecules in solution-processed OLEDs. Originally these devices were to be used in magnetoresistance studies, but the project took a different path when the devices were more efficient than expected. The efficient use of small molecules in solution-processed OLEDs is highlighted, which at the time was not often the case. Also, the important observation of the effect of solvent choice on the resultant film is emphasized, with discussion of the likely cause of these effects. Microcavity OLEDs are introduced in which the transparent anode ITO is replaced with semi-transparent thin silver, which creates an optical cavity within the devices. The goal was to expand a previous work that created an on-chip spectrometer covering wavelengths 493 to 639 nm. In this case, a spin-coated mixed emitting layer (EML) is used, consisting of a polymer and a small molecule that both emit in the near UV and blue. The resulting combined spectra gives a wide band that can be used to create narrow microcavity emission peaks of 373 to 469 nm, depending on the device thickness (i.e. the cavity’s optical length). In the process of this effort, the mixed EML presented interesting complexities that we attempt to explain via simulation and morphology study.

Hellerich, Emily [Ames Laboratory] [Ames Laboratory

2013-05-15T23:59:59.000Z

413

Light emitting diode with porous SiC substrate and method for fabricating  

DOE Patents [OSTI]

A method and apparatus for forming a porous layer on the surface of a semiconductor material wherein an electrolyte is provided and is placed in contact with one or more surfaces of a layer of semiconductor material. The electrolyte is heated and a bias is introduced across said electrolyte and the semiconductor material causing a current to flow between the electrolyte and the semiconductor material. The current forms a porous layer on the one or more surfaces of the semiconductor material in contact with the electrolyte. The semiconductor material with its porous layer can serve as a substrate for a light emitter. A semiconductor emission region can be formed on the substrate. The emission region is capable of emitting light omnidirectionally in response to a bias, with the porous layer enhancing extraction of the emitting region light passing through the substrate.

Li, Ting; Ibbetson, James; Keller, Bernd

2005-12-06T23:59:59.000Z

414

Advanced method for increasing the efficiency of white light quantum dot LEDs  

SciTech Connect (OSTI)

Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which, respectively, diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal processing (PTP), reduces the number of point defects while maintaining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of theQD nanoparticles. The current research uses a thermal model to predict annealing temperatures during PTP and demonstrates up to a 300% increase in photoluminescence for QDs on passive substrates.

Duty, Chad E [ORNL; Bennett, Charlee J C [ORNL; Sabau, Adrian S [ORNL; Jellison Jr, Gerald Earle [ORNL; Boudreaux, Philip R [ORNL; Walker, Steven C [ORNL; Ott, Ronald D [ORNL

2011-01-01T23:59:59.000Z

415

INSTITUTE OF PHYSICS PUBLISHING MEASUREMENT SCIENCE AND TECHNOLOGY Meas. Sci. Technol. 13 (2002) 8491 PII: S0957-0233(02)28495-7  

E-Print Network [OSTI]

.iop.org/MST/13/84 Abstract An inexpensive and portable pulsed light emitting diode (LED) source with variable availableintheformofindiumgalliumnitridebasedcompound semiconductors [5] used to fabricate laser diodes and light emitting diodes (LEDs). The dc output

Strathclyde, University of

416

THE LUMINA PROJECT http://light.lbl.gov  

E-Print Network [OSTI]

components for the LED lights. #12;2 Introduction Solid-state lighting based on light emitting diode (LED

Jacobson, Arne

417

Vision Research 41 (2001) 427439 Characterization and use of a digital light projector for vision  

E-Print Network [OSTI]

. For example, a light emitting diode (LED)-based stimulator has many ideal characteristics. LEDs have high

Brainard, David H.

418

E-Print Network 3.0 - algan-based laser diodes Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

GaN and GaNAlGaN quantum structures for UV electroabsorption modulators Summary: optoelectronics industry.1,2 In the visible spectral range, light emitting diodes,3 laser...

419

LED traffic lights: New technology signals major energy savings  

SciTech Connect (OSTI)

Using light-emitting diode technology to replace incandescent lamps in traffic signals promises energy savings upwards of 60 percent for each of the estimated quarter of a million controlled intersections in the United States. LED units use only 9 to 25 watts instead of the 67 to 150 watts used by each incandescent lamp. Though their first cost is relatively high, energy savings result in paybacks of 1 to 5 years. LED retrofit kits are available for red signal disks and arrows, and installations in several states have proven successful, although minor improvements are addressing concerns about varying light output and controller circuitry. Retrofitting green lamps is not yet feasible, because color standards of the Institute of Traffic Engineers cannot be met with existing LED technology. Yellow lamps have such low duty factors (they`re on only 3 percent of the time) that retrofitting with LED signals is not cost-effective. LEDs last much longer than incandescents, allowing municipalities to not only reduce their electricity bills, but to save on maintenance costs as well. As further incentive, some utilities are beginning to implement rebate programs for LED traffic signal retrofits. Full approval of LED units is still awaited from the Institute of Traffic Engineers (ITE), the standard-setting body for traffic safety devices. Local and state governments ultimately decide what specifications to require for traffic lights, and the growing body of successful field experience with LEDs appears to be raising their comfort level with the technology. The California Department of Transportation is developing an LED traffic light specification, and two California utilities, Southern California Edison and Pacific Gas and Electric, have provided rebates for some pilot installations.

Houghton, D.

1994-12-31T23:59:59.000Z

420

LOW-COST LED LUMINAIRE FOR GENERAL ILLUMINATION  

SciTech Connect (OSTI)

During this two-year Solid-State Lighting (SSL) Manufacturing R&D project Cree developed novel light emitting diode (LED) technologies contributing to a cost-optimized, efficient LED troffer luminaire platform emitting at ~3500K correlated color temperature (CCT) at a color rendering index (CRI) of >90. To successfully achieve program goals, Cree used a comprehensive approach to address cost reduction of the various optical, thermal and electrical subsystems in the luminaire without impacting performance. These developments built on Cree’s high- brightness, low-cost LED platforms to design a novel LED component architecture that will enable low-cost troffer luminaire designs with high total system efficacy. The project scope included cost reductions to nearly all major troffer subsystems as well as assembly costs. For example, no thermal management components were included in the troffer, owing to the optimized distribution of compact low- to mid-power LEDs. It is estimated that a significant manufacturing cost savings will result relative to Cree’s conventional troffers at the start of the project. A chief project accomplishment was the successful development of a new compact, high-efficacy LED component geometry with a broad far-field intensity distribution and even color point vs. emission angle. After further optimization and testing for production, the Cree XQ series of LEDs resulted. XQ LEDs are currently utilized in Cree’s AR series troffers, and they are being considered for use in other platforms. The XQ lens geometry influenced the independent development of Cree’s XB-E and XB-G high-voltage LEDs, which also have a broad intensity distribution at high efficacy, and are finding wide implementation in Cree’s omnidirectional A-lamps.

Lowes, Ted

2014-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Antennas in the optical range will improve the efficiency of light-emitting devices.  

E-Print Network [OSTI]

absorption cross-sections and quan- tum yields in photovoltaics, releasing energy efficiently from nanoscaleAntennas in the optical range will improve the efficiency of light-emitting devices. The purpose frequencies. It is hoped that optical antennas can increase the efficiency of light-matter interactions

Novotny, Lukas

422

A Cable-less Interaction Device for AR and VR Environments H. T. Regenbrechta  

E-Print Network [OSTI]

with bright Light Emitting Diodes (LEDs) mounted at each end. Using computer vision techniques, these LEDs of this we have developed the Magic Pen interface, where a real pen with Light Emitting Diodes (LEDs) mounted

Poupyrev, Ivan

423

Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals  

E-Print Network [OSTI]

Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.

V. A. Batarin; J. Butler; A. M. Davidenko; A. A. Derevschikov; Y. M. Goncharenko; V. N. Grishin; V. A. Kachanov; A. S. Konstantinov; V. I. Kravtsov; Y. Kubota; V. S. Lukanin; Y. A. Matulenko; Y. M. Melnick; A. P. Meschanin; N. E. Mikhalin; N. G. Minaev; V. V. Mochalov; D. A. Morozov; L. V. Nogach; A. V. Ryazantsev; P. A. Semenov; V. K. Semenov; K. E. Shestermanov; L. F. Soloviev; S. Stone; A. V. Uzunian; A. N. Vasiliev; A. E. Yakutin; J. Yarba

2005-04-13T23:59:59.000Z

424

High Efficiency LED Lamp for Solid-State Lighting  

SciTech Connect (OSTI)

This report contains a summary of technical achievements during a three-year project to demonstrate high efficiency, solid-state lamps based on gallium nitride/silicon carbide light-emitting diodes. Novel chip designs and fabrication processes are described for a new type of nitride light-emitting diode with the potential for very high efficiency. This work resulted in the demonstration of blue light-emitting diodes in the one watt class that achieved up to 495 mW of light output at 350 mA drive current, corresponding to quantum and wall plug efficiencies of 51% and 45%, respectively. When combined with a phosphor in Cree's 7090 XLamp package, these advanced blue-emitting devices resulted in white light-emitting diodes whose efficacy exceeded 85 lumens per watt. In addition, up to 1040 lumens at greater than 85 lumens per watt was achieved by combining multiple devices to make a compact white lamp module with high optical efficiency.

James Ibbetson

2006-12-31T23:59:59.000Z

425

LED Surgical Task Lighting Scoping Study: A Hospital Energy Alliance Project  

SciTech Connect (OSTI)

Tungsten-halogen (halogen) lamps have traditionally been used to light surgical tasks in hospitals, even though they are in many respects ill-suited to the application due to the large percentage of radiant energy outside the visible spectrum and issues with color rendering/quality. Light-emitting diode (LED) technology offers potential for adjustable color and improved color rendition/quality, while simultaneously reducing side-effects from non-visible radiant energy. It also has the potential for significant energy savings, although this is a fairly narrow application in the larger commercial building energy use sector. Based on analysis of available products and Hospital Energy Alliance member interest, it is recommended that a product specification and field measurement procedure be developed for implementation in demonstration projects.

Tuenge, Jason R.

2011-01-17T23:59:59.000Z

426

Spontaneous emission factor for semiconductor superluminescent diodes Yongsheng Zhao, Weihua Han, Junfeng Song, Xuemei Li, Yang Liu, Dingsan Gao,  

E-Print Network [OSTI]

Spontaneous emission factor for semiconductor superluminescent diodes Yongsheng Zhao, Weihua Han emission factor is an important parameter for the characterization of semiconductor light emitting devices difference involved in each device. In this article, the spontaneous emission factor for superluminescent

Cao, Hui

427

Entangled Light Emission From a Diode  

SciTech Connect (OSTI)

Electrically-driven entangled photon generation is demonstrated for the first time using a single semiconductor quantum dot embedded in a light emitting diode structure. The entanglement fidelity is shown to be of sufficient quality for applications such as quantum key distribution.

Stevenson, R. M.; Shields, A. J. [Toshiba Research Europe Limited, 208 Cambridge Science Park, Cambridge CB4 0GZ (United Kingdom); Salter, C. L. [Toshiba Research Europe Limited, 208 Cambridge Science Park, Cambridge CB4 0GZ (United Kingdom); Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Farrer, I.; Nicoll, C. A.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2011-12-23T23:59:59.000Z

428

Organic light-emitting device with a phosphor-sensitized fluorescent emission layer  

DOE Patents [OSTI]

The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters. The emissive region of the devices of the present invention comprise at least one phosphor-sensitized layer which has a combined emission from a phosphorescent emitter and a fluorescent emitter. In preferred embodiments, the invention relates to white-emitting OLEDS (WOLEDs).

Forrest, Stephen (Ann Arbor, MI); Kanno, Hiroshi (Osaka, JP)

2009-08-25T23:59:59.000Z

429

Patterned three-color ZnCdSeZnCdMgSe quantum-well structures for integrated full-color and white light emitters  

E-Print Network [OSTI]

. This result demonstrates the feasibility of fabricating integrated full-color light emitting diode and laser American Institute of Physics. S0003-6951 00 04149-8 Light emitting diodes LEDs and laser diodes LDs having

430

White LED with High Package Extraction Efficiency  

SciTech Connect (OSTI)

The goal of this project is to develop a high efficiency phosphor converting (white) Light Emitting Diode (pcLED) 1-Watt package through an increase in package extraction efficiency. A transparent/translucent monolithic phosphor is proposed to replace the powdered phosphor to reduce the scattering caused by phosphor particles. Additionally, a multi-layer thin film selectively reflecting filter is proposed between blue LED die and phosphor layer to recover inward yellow emission. At the end of the project we expect to recycle approximately 50% of the unrecovered backward light in current package construction, and develop a pcLED device with 80 lm/W{sub e} using our technology improvements and commercially available chip/package source. The success of the project will benefit luminous efficacy of white LEDs by increasing package extraction efficiency. In most phosphor-converting white LEDs, the white color is obtained by combining a blue LED die (or chip) with a powdered phosphor layer. The phosphor partially absorbs the blue light from the LED die and converts it into a broad green-yellow emission. The mixture of the transmitted blue light and green-yellow light emerging gives white light. There are two major drawbacks for current pcLEDs in terms of package extraction efficiency. The first is light scattering caused by phosphor particles. When the blue photons from the chip strike the phosphor particles, some blue light will be scattered by phosphor particles. Converted yellow emission photons are also scattered. A portion of scattered light is in the backward direction toward the die. The amount of this backward light varies and depends in part on the particle size of phosphors. The other drawback is that yellow emission from phosphor powders is isotropic. Although some backward light can be recovered by the reflector in current LED packages, there is still a portion of backward light that will be absorbed inside the package and further converted to heat. Heat generated in the package may cause a deterioration of encapsulant materials, affecting the performance of both the LED die and phosphor, leading to a decrease in the luminous efficacy over lifetime. Recent studies from research groups at Rensselaer Polytechnic Institute found that, under the condition to obtain a white light, about 40% of the light is transmitted outward of the phosphor layer and 60% of the light is reflected inward.1,2 It is claimed that using scattered photon extraction (SPE) technique, luminous efficacy is increased by 60%. In this project, a transparent/translucent monolithic phosphor was used to replace the powdered phosphor layer. In the normal pcLED package, the powdered phosphor is mixed with silicone either to be deposited on the top of LED die forming a chip level conversion (CLC) white LED or to be casted in the package forming a volume conversion white LED. In the monolithic phosphors there are no phosphor powder/silicone interfaces so it can reduce the light scattering caused by phosphor particles. Additionally, a multi-layer thin film selectively reflecting filter is inserted in the white LED package between the blue LED die and phosphor layer. It will selectively transmit the blue light from the LED die and reflect the phosphor's yellow inward emission outward. The two technologies try to recover backward light to the outward direction in the pcLED package thereby improving the package extraction efficiency.

Yi Zheng; Matthew Stough

2008-09-30T23:59:59.000Z

431

LED exit signs: Improved technology leads the way to energy savings  

SciTech Connect (OSTI)

Recent innovations in light-emitting diode (LED) exit signs may make LED signs the best choice among the energy efficient options available. In the past, LED signs have offered low power consumption, projected long lamp life, and low maintenance requirements. Now, the best of the LED signs also offer improved optical designs that reduce their already low power consumption while improving visibility and appearance, and even reduce their cost. LED exit signs are gaining market share, and E Source expects this technology to eventually dominate over incandescent, compact fluorescent, and electroluminescent signs. More research is needed, however, to confirm manufacturers` claims of 20-year operating lives for LED signs. Conservative estimates place the number of exit signs in US buildings at about 40 million. Although each sign represents a very small part of a building`s load, exit signs are ready targets for energy efficiency upgrades -- they operate continuously and most use inefficient incandescent sources. With an LED sign, annual energy and maintenance costs can be reduced by more than 90 percent compared to a typical incandescent sign. Low annual costs help to offset the LED sign`s relatively high first cost. More than 25 utilities offer DSM incentives for energy efficient exit signs, and efficient alternatives are becoming more readily available. Recent improvements in optical designs enable many LED signs to visually out perform other sources. In addition to these benefits, LED exit signs have lower life cycle cost than most other options. The biggest barrier to their success, however, is that their first cost has been considerably higher than competing technologies. LED sign prices are falling rapidly, though, because manufacturers are continually improving optical designs of the fixtures to use fewer LEDs and thus even less energy while providing better performance.

Sardinsky, R.; Hawthorne, S.

1994-12-31T23:59:59.000Z

432

doi: 10.1149/1.3250436 2010, Volume 13, Issue 1, Pages H5-H7.Electrochem. Solid-State Lett.  

E-Print Network [OSTI]

and light emitting diode LED applica- tions, has been proposed. © 2009 The Electrochemical Society. DOI: 10, the need still exists for a highly efficient true green light-emitting diode LED in the wavelength range

Woodall, Jerry M.

433

Arnold Schwarzenegger LIGHTING RESEARCH PROGRAM  

E-Print Network [OSTI]

Project Summaries ELEMENT 2: ADVANCE LIGHTING TECHNOLOGIES PROJECT 2.1 LIGHT EMITTING DIODE (LED light emitting diodes (LED) technology for general lighting applications by developing a task lamp

434

J. Phys. III France 2 (1992) 1591-1603 SEPTEMBER 1992, PAGE 1591 Classification  

E-Print Network [OSTI]

of the source. Light emitting diodes (LED) are thermal Gaussian sources. The optical bandwidth AA of a surface

Boyer, Edmond

1992-01-01T23:59:59.000Z

435

Musical Applications of Electric Field Sensing Joseph A. Paradiso and Neil Gershenfeld  

E-Print Network [OSTI]

in a variety of musical projects. These range from simple hand trackers using an light-emitting diode (LED

436

IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE MAY/JUNE 2006 570739-5175/06/$20.002006IEEE A Novel Method  

E-Print Network [OSTI]

consists of an infrared light-emitting diode (LED) and a photodiode that can be clamped to the ear lobes

437

Jimmy Chau , Thomas Little Multimedia Communications Laboratory, Electrical and Computer Engineering, Boston University, Boston, MA  

E-Print Network [OSTI]

Communication Light-emitting diodes (LEDs) can be used to both provide general illumination and transmit high

Little, Thomas

438

A Novel Neighbor Discovery Protocol for Ultraviolet Wireless Networks  

E-Print Network [OSTI]

in terms of building advanced low cost, low power and small size light emitting diodes (LEDs) that operate

Krishnamurthy, Srikanth

439

Mounir Boukadoum Department of computer science  

E-Print Network [OSTI]

by exciting the unknown substance with light emitting diodes (LED) whose intensity is CDMA coded for noise

Fayomi, Christian

440

Structural recovery of ion implanted ZnO nanowires G. Perillat-Merceroz,1, 2, a)  

E-Print Network [OSTI]

applications, ZnO nanowires are studied for making light- emitting diodes (LEDs) because of the advantages

Boyer, Edmond

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Segmentation of Crystalline Lens in Photorefraction Video Mark Wendt and Shishir K. Shah  

E-Print Network [OSTI]

of infrared light emitting diodes (IR-LED) is located on this occlud- ing device. The system of video camera

442

A Statistics-Guided Approach to Precise Characterization of Nanowire  

E-Print Network [OSTI]

sensors,7 solar cells,8 nanogen- erators,9 light-emitting diodes (LEDs),10 la- sers,11 and biomarkers12

Qian, Peter Z. G.

443

California's Energy Future - The View to 2050  

E-Print Network [OSTI]

Lawrence Livermore National Laboratory LDV Light-duty vehicles LED light emitting diode LWR Light water reactor NIF

2011-01-01T23:59:59.000Z

444

California’s Energy Future: The View to 2050 - Summary Report  

E-Print Network [OSTI]

Lawrence Livermore National Laboratory LDV Light-duty vehicles LED light emitting diode LWR Light water reactor NIF

Yang, Christopher

2011-01-01T23:59:59.000Z

445

letters to nature NATURE |VOL 404 |2 MARCH 2000 |www.nature.com 61  

E-Print Network [OSTI]

studies of the rods, and possibly in applications such as light-emitting diodes (LEDs) and photo- voltaic

Henderson, Gideon

446

Guided optical modes in randomly textured ZnO thin films imaged by near-field scanning optical K. Bittkau* and R. Carius  

E-Print Network [OSTI]

relevance. In particular, when designing thin-film solar cells and light emitting diodes LEDs , ran- domly

Peinke, Joachim

447

Research Frontiers Cutting-Edge Research  

E-Print Network [OSTI]

Shale Gas Fracturing with carbon dioxide instead of water. RESOURCE-ENG The Light Emitting Diode (LED

Takada, Shoji

448

Journal of Neuroscience Methods 133 (2004) 127134 Methods for chronic neural recording in the  

E-Print Network [OSTI]

into the dorsolateral region of the goldfish or cichlid telencephalon. An infrared light emitting diode (LED) was also

449

Restorative Neurology and Neuroscience 28 (2010) 259270 259 DOI 10.3233/RNN-2010-0488  

E-Print Network [OSTI]

; kHz: kilohertz; LED: light emitting diode; cd: candela; m: meter; cm: centimeter; ms: millisecond; d

Wallace, Mark

450

The neurological basis of visual neglect A. David Milnera  

E-Print Network [OSTI]

:000­000 Abbreviations LED light emitting diode PPC posterior parietal cortex STG superior temporal gyrus SWM spatial

McIntosh, Rob

451

Near Infrared Surface Plasmon Resonance Phase Imaging and Nanoparticle-Enhanced Surface Plasmon Resonance Phase Imaging  

E-Print Network [OSTI]

utilized a near-infrared 860 nm light emitting diode (LED) light source and a wedge depolarizer to create

452

Enhancing the Field of View Limitation of Visible Light Communication-based Platoon  

E-Print Network [OSTI]

. In the mean time, Light Emitting Diode (LED) has become very common in automotive lighting due to its long

Boyer, Edmond

453

WASTE DESCRIPTION TYPE OF PROJECT POUNDS REDUCED,  

E-Print Network [OSTI]

to the manufacturer . Replaced with energy efficient light emitting diode (LED) signs. Project reduced risk of tritium

454

Designing Interactive Lighting Dzmitry Aliakseyeu, Bernt Meerbeek, Jon  

E-Print Network [OSTI]

The Light Emitting Diode (LED) has caused a profound change within the lighting industry. This is due

455

STATE OF CALIFORNIA --THE RESOURCES AGENCY Edmund G. Brown Jr. CALIFORNIA ENERGY COMMISSION  

E-Print Network [OSTI]

as a residential high efficacy luminaire using Light Emitting Diode (LED) as the light source (as defined in IES LM

456

Detecting Exercise Induced Stress using the Photoplethysmogram Stephen Paul Linder*  

E-Print Network [OSTI]

illuminates the skin with light from a Light Emitting Diode (LED), and measures the amount of light either

Linder, Stephen

457

Das Experiment: Quantitative Versuche zur Farbmischung  

E-Print Network [OSTI]

. _______________________________ *LED = Light emitting diode Farbmischexperimente geben eine Fülle von Informationen über die spektralen

Menzel, Randolf - Institut für Biologie

458

Sixth International Conference on Solid State Lighting, edited by Ian T. Ferguson, Nadarajah Narendran, Tsunemasa Taguchi, Ian E. Ashdown,  

E-Print Network [OSTI]

commercial white light emitting diodes (LEDs) rely on complicated fabrication methods to produce white light: Cadmium Selenide, Nanocrystal, Photoluminescence, Phosphor, White Light, Light Emitting Diode, LED 1. INTRODUCTION 1.1 Solid state lighting Solid state lighting, in the form of white light emitting diodes (LEDs

Weiss, Sharon

459

Fundamental Studies and Development of III-N Visible LEDs for High-Power Solid-State Lighting Applications  

SciTech Connect (OSTI)

The goal of this program is to understand in a fundamental way the impact of strain, defects, polarization, and Stokes loss in relation to unique device structures upon the internal quantum efficiency (IQE) and efficiency droop (ED) of III-nitride (III-N) light-emitting diodes (LEDs) and to employ this understanding in the design and growth of high-efficiency LEDs capable of highly-reliable, high-current, high-power operation. This knowledge will be the basis for our advanced device epitaxial designs that lead to improved device performance. The primary approach we will employ is to exploit new scientific and engineering knowledge generated through the application of a set of unique advanced growth and characterization tools to develop new concepts in strain-, polarization-, and carrier dynamics-engineered and low-defect materials and device designs having reduced dislocations and improved carrier collection followed by efficient photon generation. We studied the effects of crystalline defect, polarizations, hole transport, electron-spillover, electron blocking layer, underlying layer below the multiplequantum- well active region, and developed high-efficiency and efficiency-droop-mitigated blue LEDs with a new LED epitaxial structures. We believe new LEDs developed in this program will make a breakthrough in the development of high-efficiency high-power visible III-N LEDs from violet to green spectral region.

Dupuis, Russell

2012-02-29T23:59:59.000Z

460

High-power LEDs based on InGaAsP/InP heterostructures  

SciTech Connect (OSTI)

High-power light-emitting diodes (LEDs) with mesa diameters of 100, 200, and 300 ?m are developed on the basis of InGaAsP/InP heterostructures. The mesas are close in shape to a truncated cone with a generatrix inclination angle of ?45° in the vicinity of the active region of the LED, with a ring etched around the mesa serving as a reflector. The emission spectra and directivity patterns of these LEDs are studied in a wide range of current densities and it is shown that radiative recombination is dominant to a current density of ?5000 A/cm{sup 2}, which makes these structures promising for the development of high-power LEDs. An emission power of ?14 mW is obtained in the continuous-wave mode (I = 0.2 A, ? = 1.1 ?m), and that of 77 mW, in the pulsed mode (I = 2 A, ? = 1.1 ?m), which corresponds to external quantum efficiencies of 6.2 and 3.4%, respectively.

Rakovics, V. [Hungarian Academy of Sciences, Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences (Hungary); Imenkov, A. N.; Sherstnev, V. V.; Serebrennikova, O. Yu.; Il’inskaya, N. D.; Yakovlev, Yu. P., E-mail: Yak@iropt1.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2014-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "leds light-emitting diodes" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Multi-Wavelength Visible Light Communication System Design Pankil Butala 1a  

E-Print Network [OSTI]

-converted light emitting diodes, or by filtering to iso- late the blue component from these sources. Multi efficient illumination devices called light emitting diodes (LED). The intensity of radiant flux emitted

Little, Thomas

462

Stable microcrystalline silicon thin-film transistors produced by the layer-by-layer P. Roca i Cabarrocas, R. Brenot, P. Bulkin, R. Vanderhaghen, B. Drvillon, and I. French  

E-Print Network [OSTI]

light-emitting diodes. © 1999 American Institute of Physics. S0021-8979 99 05324-4 I. INTRODUCTION, TFTs for active matrix addressing of organic and polymer light- emitting diodes LEDs must also have

Boyer, Edmond

463

First Results with eBlocks: Embedded Systems Building Blocks  

E-Print Network [OSTI]

, and other types ­ and output devices ­ light-emitting diodes, beeping speakers, or even electric relays a light-emitting diode (LED), sounding a beep, or turning on an electric relay that controls an electric

Vahid, Frank

464

Self-Calibrating Wide Color Gamut High Dynamic Range Display Helge Seetzen1/2  

E-Print Network [OSTI]

those using light emitting diodes. This paper describes a combination of sensor mechanisms colored light elements are used. This is especially true if light emitting diodes (LEDs) are used instead

Heidrich, Wolfgang

465

Your article is protected by copyright and all rights are held exclusively by Springer  

E-Print Network [OSTI]

campaign, demonstrated that a cavity ring down spectrometer with a light emitting diode light source (LED replaced with a light emitting diode. Six independent calibrations demonstrated the instrument's linearity

Dickerson, Russell R.

466

8, 1066510695, 2008 High finesse optical  

E-Print Network [OSTI]

of a compact and power efficient light emitting diode based broadband Cavity Enhanced Differential Optical a light emitting diode (LED) as light source particularly the precautions which have to be satisfied

Boyer, Edmond

467

Solar voltaic research P. D. (Dan) Dapkus is the W. M. Keck Professor of Engineering in the Ming Hsieh Department  

E-Print Network [OSTI]

D in Physics. He has worked at Bell Laboratories (1970 ­ 1976) on light emitting diode technology Nanoscience (CEN) will create low cost, high efficiency solar cells and light emitting diodes (LEDs

Levi, Anthony F. J.

468

Atmos. Chem. Phys., 10, 39013914, 2010 www.atmos-chem-phys.net/10/3901/2010/  

E-Print Network [OSTI]

on the construction and testing of a com- pact and power efficient light emitting diode based broad- band Cavity ­ measure any gas detectable by DOAS. We will discuss the advantages of using a light emitting diode (LED

Meskhidze, Nicholas

469

Energy Department Offers $10 Million for Energy-Saving Lighting...  

Broader source: Energy.gov (indexed) [DOE]

technologies. This funding will help accelerate the development of high-quality light-emitting diode (LED) and organic light-emitting diode (OLED) products with the potential to...

470

Energy Department Announces $10 Million for Innovative, Energy...  

Energy Savers [EERE]

the country. This funding will accelerate the development of high-quality light-emitting diode (LED) and organic light-emitting diode (OLED) products with the potential to...

471

Energy Department Announces $10 Million to Advance Innovative...  

Broader source: Energy.gov (indexed) [DOE]

the country. This funding will help accelerate the development of high-quality light-emitting diode (LED) and organic light-emitting diode (OLED) products with the potential to...

472

Surface plasmon enhanced InGaN light emitter Koichi Okamoto*a  

E-Print Network [OSTI]

is a very promising method for developing the super bright light emitting diodes (LEDs). Moreover, we foundGaN/GaN, light emitting diode, quantum well, internal quantum efficiency, solid-state light source 1. INTRODUCTION Since 1993, InGaN quantum wells (QW)-based light emitting diodes (LEDs) have been continuously

Okamoto, Koichi

473

applying ventilated double-skin: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a complicated task, since... sweatingcondensation on the water coil. 3.06 LED (Light Emitting Diode) Lighting The building is illuminated using extremely energy efficient LED?s...

474

Abbreviated epitaxial growth mode (AGM) method for reducing cost and improving quality of LEDs and lasers  

DOE Patents [OSTI]

The use of an abbreviated GaN growth mode on nano-patterned AGOG sapphire substrates, which utilizes a process of using 15 nm low temperature GaN buffer and bypassing etch-back and recovery processes during epitaxy, enables the growth of high-quality GaN template on nano-patterned AGOG sapphire. The GaN template grown on nano-patterned AGOG sapphire by employing abbreviated growth mode has two orders of magnitude lower threading dislocation density than that of conventional GaN template grown on planar sapphire. The use of abbreviated growth mode also leads to significant reduction in cost of the epitaxy. The growths and characteristics of InGaN quantum wells (QWs) light emitting diodes (LEDs) on both templates were compared. The InGaN QWs LEDs grown on the nano-patterned AGOG sapphire demonstrated at least a 24% enhancement of output power enhancement over that of LEDs grown on conventional GaN templates.

Tansu, Nelson; Chan, Helen M; Vinci, Richard P; Ee, Yik-Khoon; Biser, Jeffrey

2013-09-24T23:59:59.000Z

475

Feedback-Controlled LED Photobioreactor for Photophysiological Studies of Cyanobacteria  

SciTech Connect (OSTI)

A custom photobioreactor (PBR) was designed to enable automatic light adjustments using computerized feedback control. A black anodized aluminum enclosure, constructed to surround the borosilicate reactor vessel, prevents the transmission of ambient light and serves as a mount for arrays of light-emitting diodes (LEDs). The high-output LEDs provide narrow-band light of either 630 or 680 nm for preferential excitation of the cyanobacterial light-harvesting pigments, phycobilin or chlorophyll a, respectively. Custom developed software BioLume provides automatic control of optical properties and a computer feedback loop can automatically adjust the incident irradiance as necessary to maintain a fixed transmitted light through the culture, based on user-determined set points. This feedback control serves to compensate for culture dynamics which have optical effects, (e.g., changing cell density, pigment adaptations) and thus can determine the appropriate light conditions for physiological comparisons or to cultivate light-sensitive strains, without prior analyses. The LED PBR may also be controlled as a turbidostat, using a feedback loop to continuously adjust the rate of media-dilution based on the transmitted light measurements, with a fast and precise response. This cultivation system gains further merit as a high-performance analytical device, using non-invasive tools (e.g., dissolved gas sensors, online mass spectrometry) to automate real-time measurements, thus permitting unsupervised experiments to search for optimal growth conditions, to monitor physiological responses to perturbations, as well as to quantitate photophysiological parameters using an in situ light-saturation response routine.

Melnicki, Matthew R.; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Stolyar, Sergey; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alex S.

2013-04-09T23:59:59.000Z

476

A portable time-domain LED fluorimeter for nanosecond fluorescence lifetime measurements  

SciTech Connect (OSTI)

Fluorescence lifetime measurements are becoming increasingly important in chemical and biological research. Time-domain lifetime measurements offer fluorescence multiplexing and improved handling of interferers compared with the frequency-domain technique. In this paper, an all solid-state, filterless, and highly portable light-emitting-diode based time-domain fluorimeter (LED TDF) is reported for the measurement of nanosecond fluorescence lifetimes. LED based excitation provides more wavelengths options compared to laser diode based excitation, but the excitation is less effective due to the uncollimated beam, less optical power, and longer latency in state transition. Pulse triggering and pre-bias techniques were implemented in our LED TDF to improve the peak optical power to over 100 mW. The proposed pulsing circuit achieved an excitation light fall time of less than 2 ns. Electrical resetting technique realized a time-gated photo-detector to remove the interference of the excitation light with fluorescence. These techniques allow the LED fluorimeter to accurately measure the fluorescence lifetime of fluorescein down to concentration of 0.5 ?M. In addition, all filters required in traditional instruments are eliminated for the non-attenuated excitation/emission light power. These achievements make the reported device attractive to biochemical laboratories seeking for highly portable lifetime detection devices for developing sensors based on fluorescence lifetime changes. The device was initially validated by measuring the lifetimes of three commercial fluorophores and comparing them with reported lifetime data. It was subsequently used to characterize a ZnSe quantum dot based DNA sensor.

Wang, Hongtao; Salthouse, Christopher D., E-mail: salthouse@ecs.umass.edu [Electrical and Computer Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Center for Personalized Health Monitoring, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Qi, Ying; Mountziaris, T. J. [Center for Personalized Health Monitoring, University of Massachusetts, Amherst, Massachusetts 01003 (United States) [Center for Personalized Health Monitoring, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Chemical Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2014-05-15T23:59:59.000Z

477

(Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1996. Two companies in  

E-Print Network [OSTI]

in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar in research and development, specialty alloys, and other applications. Optoelectronic devices were used

478

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2006. One company in Utah  

E-Print Network [OSTI]

circuits. Optoelectronic devices, which include light-emitting diodes (LEDs), laser diodes, photodetectors, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace

479

(Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1998. Two companies in  

E-Print Network [OSTI]

in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

480

(Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2000. Two companies in  

E-Print Network [OSTI]

in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

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481

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2008. One company in Utah  

E-Print Network [OSTI]

circuits (ICs). Optoelectronic devices, which include laser diodes, light-emitting diodes (LEDs and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

482

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2005. One company in Utah  

E-Print Network [OSTI]

circuits. Optoelectronic devices, which include light-emitting diodes (LEDs), laser diodes, photodetectors, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace

483

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2007. One company in Utah  

E-Print Network [OSTI]

circuits (ICs). Optoelectronic devices, which include light-emitting diodes (LEDs), laser diodes and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

484

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2009. One company in Utah  

E-Print Network [OSTI]

circuits (ICs). Optoelectronic devices, which include laser diodes, light-emitting diodes (LEDs and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

485

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2010. One company in Utah  

E-Print Network [OSTI]

circuits (ICs). Optoelectronic devices, which include laser diodes, light-emitting diodes (LEDs and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

486

(Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1999. Two companies in  

E-Print Network [OSTI]

in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

487

(Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1997. Two companies in  

E-Print Network [OSTI]

in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar and development, specialty alloys, and other applications. Optoelectronic devices were used in areas

488

alternative ambient illumination: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diodes (LEDs) are energy-efficient solid- state Illumination Light-emitting diode Minimal access surgery Solid-state semiconductor In the 1950s Rosso,...

489

DESIGN PROJECTS 2012-2013 1. Quantum Dot Light Emitting Diodes (Dr. K. Deshpande, Dow Chemical Company/Prof. M.  

E-Print Network [OSTI]

: a. Must perform acoustical, thermal, and fire barrier functions. b. Must not be heavy; New amounts of water. h. Must not have adverse environmental and/or health/safety effects either during an extraterrestrial SOFC station to be deployed on Titan to supply electrical power to terrestrial rovers

Weaver, John H.

490

Development of hybrid organic-inorganic light emitting diodes using conducting polymers deposited by oxidative chemical vapor deposition process  

E-Print Network [OSTI]

Difficulties with traditional methods of synthesis and film formation for conducting polymers, many of which are insoluble, motivate the development of CVD methods. Indeed, conjugated polymers with rigid linear backbones ...

Chelawat, Hitesh

2010-01-01T23:59:59.000Z

491

AC-driven, color-and brightness-tunable organic light-emitting diodes constructed from an electron only device  

E-Print Network [OSTI]

a charge generation layer into an electron only device to form an n-i-p-i-n structure. It is shown that an electron only device (EOD), which can be considered as an n-i-n structure. The low injection barrier with a negative bias across the device while the holes are blocked at the other electrode. Therefore, the electron

Demir, Hilmi Volkan

492

Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light-emitting Diodes  

E-Print Network [OSTI]

Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light and Technology, Clear Water Bay, Kowloon, Hong Kong, China ABSTRACT Aluminum doped zinc oxide (AZO that MTDATA matches better with AZO than CuPc, which served as hole injection layer. Keywords: Aluminum doped

493

Abstract --This letter presents highly-polarized edge light emitting diodes with high-confinement, strained, multiple  

E-Print Network [OSTI]

power. We characterize InGaAsP MQW ELED devices with different lengths and optical confinement factors that transitions involving the HH band provide gain/absorption to TE polarized light and those involving the LH band provide gain/absorption mostly to TM polarized light, and to a lesser extent to TE light [7

Coldren, Larry A.

494

Characterizing organometallic-vapor-phase-epitaxy-grown indium gallium nitride islands on gallium nitride for light emitting diode applications.  

E-Print Network [OSTI]

??The indium-gallium-nitride on gallium-nitride (InGaN/GaN) materials system is a promising candidate for providing a high intensity, high efficiency solution to the yet unsolved problem of… (more)

Anderson, Kathy Perkins Jenkins

2011-01-01T23:59:59.000Z

495

Temperature-and size-dependent characteristics in ultrathin inorganic light-emitting diodes assembled by transfer printing  

E-Print Network [OSTI]

lateral dimensions (l-ILEDs) could provide attractive alternatives.5,7­12 Such classes of devices can, subsequently released by LLO. The devices use 200 nm p-GaN/140 nm multiple quantum wells (MQW)/400 nm spacer/2

Rogers, John A.

496

Modulating emission intensity of GaN-based green light emitting diodes on c-plane sapphire  

SciTech Connect (OSTI)

The asymmetric dual-wavelength (green/blue) coupled InGaN/GaN multiple quantum wells were proposed to modulate the green emission intensity. Electroluminescent measurements demonstrate the conspicuous increment of the green light intensity by decreasing the coupled barrier thickness. This was partly attributed to capture of more carriers when holes tunnel across the thinner barrier from the blue quantum wells, as a hole reservoir, to the green quantum wells. While lower effective barrier height of the blue quantum wells benefits improved hole transportation from p-GaN to the active region. Efficiency droop of the green quantum wells was partially alleviated due to the enhanced injection efficiency of holes.

Du, Chunhua; Ma, Ziguang; Zhou, Junming; Lu, Taiping; Jiang, Yang; Jia, Haiqiang; Liu, Wuming; Chen, Hong, E-mail: hchen@iphy.ac.cn [Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-04-14T23:59:59.000Z

497

Design and optimization of a light-emitting diode projection micro-stereolithography three-dimensional manufacturing system  

E-Print Network [OSTI]

The rapid manufacture of complex three-dimensional micro-scale components has eluded researchers for decades. Several additive manufacturing options have been limited by either speed or the ability to fabricate true ...

Lee, Howon