National Library of Energy BETA

Sample records for high-efficiency organic solar

  1. Fabrication of Organic-inorganic Perovskites for Highly Efficient Solar

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

    Cells and Light Emitting Diodes | MIT-Harvard Center for Excitonics Fabrication of Organic-inorganic Perovskites for Highly Efficient Solar Cells and Light Emitting Diodes January 19, 2016 at 4:30pm/36-428 Sandeep Pathak Oxford University Pathak The unprecedented worldwide interest in organic-inorganic lead halide-based perovskite (HC(NH2)2PbX3 or CH3NH3PbX3) solar cells is rooted in its solution process-ability at low temperature as well as its extraordinary device performance. Perovskite

  2. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print Wednesday, 27 March 2013 00:00 The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the

  3. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  4. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  5. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  6. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  7. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  8. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  9. The Importance of Domain Size and Purity in High-Efficiency Organic Solar

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

    Cells The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells Print The efficiency of polymer/organic photovoltaic cells hinges on excitons-electron/hole pairs energized by sunlight-getting to the interfaces of donor and acceptor domains quickly, before recombining. At the interfaces, they become free charges that must then reach device electrodes. With the discovery of mixed domains of donor and acceptor molecules, many have pictured the excitons' journey as easy

  10. Highly efficient inverted organic solar cells using amino acid modified indium tin oxide as cathode

    SciTech Connect (OSTI)

    Li, Aiyuan; Nie, Riming; Deng, Xianyu; Wei, Huaixin; Li, Yanqing; Tang, Jianxin; Zheng, Shizhao; Wong, King-Young

    2014-03-24

    In this paper, we report that highly efficient inverted organic solar cells were achieved by modifying the surface of indium tin oxide (ITO) using an amino acid, Serine (Ser). With the modification of the ITO surface, device efficiency was significantly enhanced from 0.63% to 4.17%, accompanied with an open circuit voltage (Voc) that was enhanced from 0.30?V to 0.55?V. Ultraviolet and X-ray photoelectron spectroscopy studies indicate that the work function reduction induced by the amino acid modification resulting in the decreased barrier height at the ITO/organic interface played a crucial role in the enhanced performances.

  11. Highly Efficient Solar Thermochemical Reaction Systems

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

    Highly Efficient, Solar Thermochemical Reaction Systems (2014 R&D 100 Award Winner) U.S. ...andfuelcells.energy.gov HIGHLY EFFICIENT, SOLAR THERMOCHEMICAL REACTION SYSTEMS Robert S ...

  12. Highly efficient organic multi-junction solar cells with a thiophene based donor material

    SciTech Connect (OSTI)

    Meerheim, Rico Krner, Christian; Leo, Karl

    2014-08-11

    The efficiency of organic solar cells can be increased by serial stacked subcells even upon using the same absorber material. For the multi-junction devices presented here, we use the small molecule donor material DCV5T-Me. The subcell currents were matched by optical transfer matrix simulation, allowing an efficiency increase from 8.3% for a single junction up to 9.7% for a triple junction cell. The external quantum efficiency of the subcells, measured under appropriate light bias illumination, is spectrally shifted due to the microcavity of the complete stack, resulting in a broadband response and an increased cell current. The increase of the power conversion efficiency upon device stacking is even stronger for large area cells due to higher influence of the resistance of the indium tin oxide anode, emphasizing the advantage of multi-junction devices for large-area applications.

  13. High Efficiency Organic Solar Cells: December 16, 2009 - February 2, 2011

    SciTech Connect (OSTI)

    Walker, K.; Joslin, S.

    2011-05-01

    Details on the development of novel organic solar cells incorporating Trimetasphere based acceptors are presented including: baseline performance for Lu-PCBEH acceptor blended with P3HT demonstrated at 4.89% PCE exceeding the 4.5% PCE goal; an increase of over 250mV in Voc was demonstrated for Lu-PCBEH blended with low band gap polymers compared to a comparable C60-PCBM device. The actual Voc was certified at 260mV higher for a low band gap polymer device using the Lu-PCBEH acceptor; and the majority of the effort was focused on development of a device with over 7% PCE. While low current and fill factors suppressed overall device performance for the low band gap polymers tested, significant discoveries were made that point the way for future development of these novel acceptor materials.

  14. Webinar: Highly Efficient Solar Thermochemical Reaction Systems |

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

    Department of Energy Highly Efficient Solar Thermochemical Reaction Systems Webinar: Highly Efficient Solar Thermochemical Reaction Systems Below is the text version of the webinar titled "Highly Efficient Solar Thermochemical Reaction Systems," originally presented on January 13, 2015. In addition to this text version of the audio, you can access the presentation slides. Amit Talapatra: Hello, everyone, and thanks for joining today's webinar. Today's webinar is being recorded, so

  15. Highly Efficient Solar Thermochemical Reaction Systems

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

    Highly Efficient, Solar Thermochemical Reaction Systems (2014 R&D 100 Award Winner) U.S. Department of Energy Fuel Cell Technologies Office 2 Question and Answer * Please type your question into the question box hydrogenandfuelcells.energy.gov HIGHLY EFFICIENT, SOLAR THERMOCHEMICAL REACTION SYSTEMS Robert S Wegeng, PI FCTO Webinar 2014 R&D 100 Award Winning Technology January 13, 2015 HIGHLY EFFICIENT, SOLAR THERMOCHEMICAL REACTION SYSTEMS Robert S Wegeng, PI FCTO Webinar January 13,

  16. Highly Efficient Solar Thermochemical Reaction Systems

    Broader source: Energy.gov [DOE]

    Download presentation slides from the DOE Fuel Cell Technologies Office webinar "Highly Efficient Solar Thermochemical Reaction Systems" held on January 13, 2015.

  17. Webinar: Highly Efficient Solar Thermochemical Reaction Systems

    Broader source: Energy.gov [DOE]

    The Fuel Cell Technologies Office will present a live webinar titled "Highly Efficient Solar Thermochemical Reaction Systems" on Tuesday, January 13, from 12:00 to 1:00 p.m. Eastern Standard Time.

  18. High Efficiency Solar Integrated Roof Membrane Product

    SciTech Connect (OSTI)

    Partyka, Eric; Shenoy, Anil

    2013-05-15

    This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

  19. High Efficiency Solar Fuels Reactor Concept | Department of Energy

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

    Solar Fuels Reactor Concept High Efficiency Solar Fuels Reactor Concept This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held ...

  20. High Efficiency Low-Cost Perovskite Solar Cell Modules

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

    High Efficiency, Low-Cost Perovskite Solar Cell Modules High Efficiency, Low-Cost Perovskite Solar Cell Modules Perovskite solar cells have the ability to greatly increase the adoption of solar power technology: * Low cost - as much as 75% less than current Si solar cells * High efficiency - equal to and possibly slightly greater than Si solar cell technology * Realization of solar panels for grid- based electricity generation * Increased adoption of solar cell technology across the world

  1. High efficiency, radiation-hard solar cells

    SciTech Connect (OSTI)

    Ager III, J.W.; Walukiewicz, W.

    2004-10-22

    The direct gap of the In{sub 1-x}Ga{sub x}N alloy system extends continuously from InN (0.7 eV, in the near IR) to GaN (3.4 eV, in the mid-ultraviolet). This opens the intriguing possibility of using this single ternary alloy system in single or multi-junction (MJ) solar cells of the type used for space-based surveillance satellites. To evaluate the suitability of In{sub 1-x}Ga{sub x}N as a material for space applications, high quality thin films were grown with molecular beam epitaxy and extensive damage testing with electron, proton, and alpha particle radiation was performed. Using the room temperature photoluminescence intensity as a indirect measure of minority carrier lifetime, it is shown that In{sub 1-x}Ga{sub x}N retains its optoelectronic properties at radiation damage doses at least 2 orders of magnitude higher than the damage thresholds of the materials (GaAs and GaInP) currently used in high efficiency MJ cells. This indicates that the In{sub 1-x}Ga{sub x}N is well-suited for the future development of ultra radiation-hard optoelectronics. Critical issues affecting development of solar cells using this material system were addressed. The presence of an electron-rich surface layer in InN and In{sub 1-x}Ga{sub x}N (0 < x < 0.63) was investigated; it was shown that this is a less significant effect at large x. Evidence of p-type activity below the surface in Mg-doped InN was obtained; this is a significant step toward achieving photovoltaic action and, ultimately, a solar cell using this material.

  2. Integrated Solar Thermochemical Reaction System for High Efficiency

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

    Production of Electricity | Department of Energy Integrated Solar Thermochemical Reaction System for High Efficiency Production of Electricity Integrated Solar Thermochemical Reaction System for High Efficiency Production of Electricity This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held April 23-25, 2013 near Phoenix, Arizona. csp_review_meeting_042313_wegeng.pdf (2.22 MB) More Documents & Publications Highly Efficient Solar

  3. Low Cost, High Efficiency Tandem Silicon Solar Cells and LEDs...

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

    Building Energy Efficiency Building Energy ... Return to Search Low Cost, High Efficiency Tandem Silicon Solar Cells and LEDs ... gaps will lead to efficient power conversion. ...

  4. High-Efficiency Solar Cogeneration with Thermophotovoltaic &...

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

    targeted 'Solar Cogeneration' technologies to maximize energy generation & energy efficiency from the building's solar insolation resources. Project presents a novel, low-cost...

  5. High-efficiency solar cell and method for fabrication

    DOE Patents [OSTI]

    Hou, H.Q.; Reinhardt, K.C.

    1999-08-31

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

  6. High-efficiency solar cell and method for fabrication

    DOE Patents [OSTI]

    Hou, Hong Q.; Reinhardt, Kitt C.

    1999-01-01

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

  7. SOLAR POWERING OF HIGH EFFICIENCY ABSORPTION CHILLER

    SciTech Connect (OSTI)

    Randy C. Gee

    2004-11-15

    This is the Final Report for two solar cooling projects under this Cooperative Agreement. The first solar cooling project is a roof-integrated solar cooling and heating system, called the Power Roof{trademark}, which began operation in Raleigh, North Carolina in late July 2002. This system provides 176 kW (50 ton) of solar-driven space cooling using a unique nonimaging concentrating solar collector. The measured performance of the system during its first months of operation is reported here, along with a description of the design and operation of this system. The second solar cooling system, with a 20-ton capacity, is being retrofit to a commercial office building in Charleston, South Carolina but has not yet been completed.

  8. Webinar January 13: Highly Efficient Solar Thermochemical Reaction Systems

    Broader source: Energy.gov [DOE]

    The Energy Department will present a live webinar entitled "Highly Efficient Solar Thermochemical Reaction Systems" on Tuesday, January 13, from 12:00 to 1:00 p.m. Eastern Standard Time.

  9. Process development for high-efficiency silicon solar cells

    SciTech Connect (OSTI)

    Gee, J.M.; Basore, P.A.; Buck, M.E.; Ruby, D.S.; Schubert, W.K.; Silva, B.L.; Tingley, J.W.

    1991-01-01

    Fabrication of high-efficiency silicon solar cells in an industrial environment requires a different optimization than in a laboratory environment. Strategies are presented for process development of high-efficiency silicon solar cells, with a goal of simplifying technology transfer into an industrial setting. The strategies emphasize the use of statistical experimental design for process optimization, and the use of baseline processes and cells for process monitoring and quality control. 8 refs.

  10. High Efficiency Multiple-Junction Solar Cells - Energy Innovation Portal

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

    Solar Photovoltaic Solar Photovoltaic Find More Like This Return to Search High Efficiency Multiple-Junction Solar Cells Sandia National Laboratories Contact SNL About This Technology Publications: PDF Document Publication Market Sheet (937 KB) Technology Marketing SummarySingle junction solar cells have limited efficiency and fail to extract maximum energy from photons outside of a specific spectral region. Higher efficiency and optical to electrical energy conversion is achieved by stacking

  11. High-Efficiency Solar Cell Concepts: Physics, Materials, and Devices

    SciTech Connect (OSTI)

    Mascarenhas, A.; Francoeur, S.; Seong, M. J.; Fluegel, B.; Zhang, Y.; Wanlass, M. W.

    2005-01-01

    Over the past three decades, significant progress has been made in the area of high-efficiency multijunction solar cells, with the effort primarily directed at current-matched solar cells in tandem. The key materials issues here have been obtaining semiconductors with the required bandgaps for sequential absorption of light in the solar spectrum and that are lattice matched to readily available substrates. The GaInP/GaAs/Ge cell is a striking example of success achieved in this area. Recently, several new approaches for high-efficiency solar cell design have emerged, that involve novel methods for tailoring alloy bandgaps, as well as alternate technologies for hetero-epitaxy of III-V's on Si. The advantages and difficulties expected to be encountered with each approach will be discussed, addressing both the materials issues and device physics whilst contrasting them with other fourth-generation solar cell concepts.

  12. Modelling and fabrication of high-efficiency silicon solar cells

    SciTech Connect (OSTI)

    Rohatgi, A.; Smith, A.W.; Salami, J.

    1991-10-01

    This report covers the research conducted on modelling and development of high-efficiency silicon solar cells during the period May 1989 to August 1990. First, considerable effort was devoted toward developing a ray-tracing program for the photovoltaic community to quantify and optimize surface texturing for solar cells. Second, attempts were made to develop a hydrodynamic model for device simulation. Such a model is somewhat slower than drift-diffusion type models like PC-1D, but it can account for more physical phenomena in the device, such as hot carrier effects, temperature gradients, thermal diffusion, and lattice heat flow. In addition, Fermi-Dirac statistics have been incorporated into the model to deal with heavy doping effects more accurately. Third and final component of the research includes development of silicon cell fabrication capabilities and fabrication of high-efficiency silicon cells. 84 refs., 46 figs., 10 tabs.

  13. Highly Efficient Multigap Solar Cell Materials - Energy Innovation Portal

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

    Highly Efficient Multigap Solar Cell Materials Lawrence Berkeley National Laboratory Contact LBL About This Technology Publications: PDF Document Publication Yu, K. M., Walukeiwicz, W., Wu J., Shan, W., Beeman, J. W., Scarpulla, M. A., Dubon, O. D., Becla, P. "Diluted II-VI Oxide Semiconductors with Multiple Band Gaps," Physical Review Letters, Vo. 91, No. 24, Dec. 12, 2003. (178 KB) Technology Marketing Summary Scientists at Berkeley Lab have invented multiband gap semiconducting

  14. NREL and Partners to Compare High-Efficiency Solar Cells from Three Nations

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

    at Sites in Colorado and Yokohama, Japan - News Releases | NREL and Partners to Compare High-Efficiency Solar Cells from Three Nations at Sites in Colorado and Yokohama, Japan April 4, 2011 Golden, Colo., April 4, 2011 - The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is partnering with major international industrial technology and solar research organizations to test how solar cells from three manufacturers perform in two geographic locations with different

  15. High-Temperature High-Efficiency Solar Thermoelectric Generators

    SciTech Connect (OSTI)

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

    Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  16. High-efficiency silicon heterojunction solar cells: Status and perspectives

    SciTech Connect (OSTI)

    De Wolf, S.; Geissbuehler, J.; Loper, P.; Martin de Nicholas, S.; Seif, J.; Tomasi, A.; Ballif, C.

    2015-05-11

    Silicon heterojunction technology (HJT) uses silicon thin-film deposition techniques to fabricate photovoltaic devices from mono-crystalline silicon wafers (c-Si). This enables energy-conversion efficiencies above 21 %, also at industrial-production level. In this presentation we review the present status of this technology and point out recent trends. We first discuss how the properties of thin hydrogenated amorphous silicon (a-Si:H) films can be exploited to fabricate passivating contacts, which is the key to high- efficiency HJT solar cells. Such contacts enable very high operating voltages, approaching the theoretical limits, and yield small temperature coefficients. With this approach, an increasing number of groups are reporting devices with conversion efficiencies well over 20 % on both-sides contacted n-type cells, Panasonic leading the field with 24.7 %. Exciting results have also been obtained on p-type wafers. Despite these high voltages, important efficiency gains can still be made in fill factor and optical design. This requires improved understanding of carrier transport across device interfaces and reduced parasitic absorption in HJT solar cells. For the latter, several strategies can be followed: Short-wavelength losses can be reduced by replacing the front a-Si:H films with wider-bandgap window layers, such as silicon alloys or even metal oxides. Long- wavelength losses are mitigated by introducing new high-mobility TCO’s such as hydrogenated indium oxide, and also by designing new rear reflectors. Optical shadow losses caused by the front metallization grid are significantly reduced by replacing printed silver electrodes with fine-line plated copper contacts, leading also to possible cost advantages. The ultimate approach to minimize optical losses is the implementation of back-contacted architectures, which are completely devoid of grid shadow losses and parasitic absorption in the front layers can be minimized irrespective of electrical

  17. High-efficiency silicon heterojunction solar cells: Status and perspectives

    SciTech Connect (OSTI)

    De Wolf, S.

    2015-04-27

    Silicon heterojunction technology (HJT) uses silicon thin-film deposition techniques to fabricate photovoltaic devices from mono-crystalline silicon wafers (c-Si). This enables energy-conversion efficiencies above 21 %, also at industrial-production level. In this presentation we review the present status of this technology and point out recent trends. We first discuss how the properties of thin hydrogenated amorphous silicon (a-Si:H) films can be exploited to fabricate passivating contacts, which is the key to high- efficiency HJT solar cells. Such contacts enable very high operating voltages, approaching the theoretical limits, and yield small temperature coefficients. With this approach, an increasing number of groups are reporting devices with conversion efficiencies well over 20 % on n-type wafers, Panasonic leading the field with 24.7 %. Exciting results have also been obtained on p-type wafers. Despite these high voltages, important efficiency gains can still be made in fill factor and optical design. This requires improved understanding of carrier transport across device interfaces and reduced parasitic absorption in HJT solar cells. For the latter, several strategies can be followed: Short- wavelength losses can be reduced by replacing the front a-Si:H films with wider-bandgap window layers, such as silicon alloys or even metal oxides. Long-wavelength losses are mitigated by introducing new high-mobility TCO’s such as hydrogenated indium oxide, and also by designing new rear reflectors. Optical shadow losses caused by the front metalisation grid are significantly reduced by replacing printed silver electrodes with fine-line plated copper contacts, leading also to possible cost advantages. The ultimate approach to minimize optical losses is the implementation of back-contacted architectures, which are completely devoid of grid shadow losses and parasitic absorption in the front layers can be minimized irrespective of electrical transport requirements. The

  18. Excitons in Highly Efficient Organic Devices | MIT-Harvard Center for

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

    Excitonics Excitons in Highly Efficient Organic Devices November 29, 2012 at 3pm/36-428 Karl Leo Department of Mathematics and Natural Sciences, Department of Physics, Technical University of Dresden bio_Karl_leo_d_e Abstract: Organic semiconductors with conjugated electron system are currently intensively investigated for optoelectronic applications. This interest is spurred by novel devices such as organic light-emitting diodes (OLED), and organic solar cells. For both devices, high

  19. Processes for producing low cost, high efficiency silicon solar cells

    DOE Patents [OSTI]

    Rohatgi, Ajeet; Chen, Zhizhang; Doshi, Parag

    1996-01-01

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. Silicon solar cell efficiencies of 16.9% have been achieved. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x.

  20. ENGINEERED ELECTRODES AND ELECTRODE-ORGANIC INTERFACES FOR HIGH-EFFICIENCY ORGANIC PHOTOVOLTAICS

    SciTech Connect (OSTI)

    Tobin J. Marks; R.P.H. Chang; Tom Mason; Ken Poeppelmeier; Arthur J. Freeman

    2008-11-13

    Organic photovoltaic (OPV) cells offer the ultimate promise of low cost, readily manufacturable, and durable solar power. While recent advances have led to cells with impressive performance levels, OPV cells have yet to break the double-digit efficiency barrier. Further gains in efficiency and durability, to that competitive with high-performance inorganic photovoltaics will require breakthroughs in transparent electrode and interfacial materials science and engineering. This project involved an integrated basic research effort carried out by an experienced and highly collaborative interdisciplinary team to address in unconventional ways, critical electrode-interfacial issues underlying OPV performance--controlling band offsets between transparent electrodes and organics, addressing current loss/leakage problems at interfaces, enhancing adhesion, interfacial stability, and device durability while minimizing cost. It synergistically combined materials and interfacial reagent synthesis, nanostructural and photovoltaic characterization, and high level quantum theory. The research foci were: 1) understanding of/development of superior transparent electrode materials and materials morphologies--i.e., better matched electronically and chemically to organic active layers, 2) understanding-based development of inorganic interfacial current-collecting/charge-blocking layers, and 3) understanding-based development of self-assembled adhesion/current-collecting/charge-blocking/cross-linking layers for high-efficiency OPV interfaces. Pursing the goal of developing the fundamental scientific understanding needed to design, fabricate, prototype and ultimately test high-efficiency OPV cells incorporating these new concepts, we achieved a record power conversion efficiency of 5.2% for an organic bulk-heterjunction solar cell.

  1. Processes for producing low cost, high efficiency silicon solar cells

    DOE Patents [OSTI]

    Rohatgi, A.; Doshi, P.; Tate, J.K.; Mejia, J.; Chen, Z.

    1998-06-16

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime {tau} and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime {tau} and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO{sub x}. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure. 28 figs.

  2. Processes for producing low cost, high efficiency silicon solar cells

    DOE Patents [OSTI]

    Rohatgi, Ajeet; Doshi, Parag; Tate, John Keith; Mejia, Jose; Chen, Zhizhang

    1998-06-16

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure.

  3. Scientists Confirm Robustness of Key Component in Ultra-High-Efficiency Solar Cell (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-05-01

    Scientists developed and tested a new, stable 1-eV metamorphic junction for a high efficiency multijunction III-V solar cell for CPV application.

  4. High Efficiency CdTe Ink-Based Solar Cells Using Nanocrystals...

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

    NREL researchers create a solution-processable "ink" to produce high-efficiency solar cells using low temperature and simple processing. Colloidal nanocrystals (NCs) provide a ...

  5. High-Efficiency Solar Thermochemical Reactor for Hydrogen Production

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

    Efficiency Solar Thermochemical Reactor for Hydrogen Production - Sandia Energy Energy ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  6. High Efficiency Organic Light Emitting Devices for Lighting

    SciTech Connect (OSTI)

    So, Franky; Tansu, Nelson; Gilchrist, James

    2013-06-30

    Incorporate internal scattering layers and microlens arrays in high efficiency OLED to achieve up to 70% EQE.

  7. High-Efficiency Low-Cost Solar Receiver for Use in a Supercritical...

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

    Low-Cost Solar Receiver for Use in a Supercritical CO2 Recompression Cycle High-Efficiency Low-Cost ... This presentation was delivered at the SunShot Concentrating Solar Power ...

  8. High-Efficiency GaAs Thin-Film Solar Cell Reliability | Department...

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

    GaAs Thin-Film Solar Cell Reliability High-Efficiency GaAs Thin-Film Solar Cell Reliability Presented at the PV Module Reliability Workshop, February 26 - 27 2013, Golden, Colorado ...

  9. High Efficiency Low-Cost Perovskite Solar Cell Modules

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

    (moisture stability not yet demonstrated) (A) Development of 3"x3" solar module temperature controlled thin-film coating * Dr. blading technique: Drag solution on hot-substrate ...

  10. High Efficiency Adsorption Chillers: High Efficiency Adsorption Cooling Using Metal Organic Heat Carriers

    SciTech Connect (OSTI)

    2010-10-01

    BEETIT Project: PNNL is incorporating significant improvements in materials that adsorb liquids or gases to design more efficient adsorption chillers. An adsorption chiller is a type of air conditioner that is powered by heat, solar or waste heat, or combustion of natural gas. Unlike typical chillers, this type has few moving parts and uses almost no electricity to operate. PNNL is designing adsorbent materials at the molecular level with at least 3 times higher refrigerant capacity and up to 20 times faster kinetics than adsorbents used in current chillers. By using the new adsorbent, PNNL is able to create a chiller that is significantly smaller, has twice the energy efficiency, and lower costs for materials and assembly time compared to conventional adsorption chillers.

  11. High-Efficiency, Commercial Ready CdTe Solar Cells

    SciTech Connect (OSTI)

    Sites, James R.

    2015-11-19

    Colorado State’s F-PACE project explored several ways to increase the efficiency of CdTe solar cells and to better understand the device physics of those cells under study. Increases in voltage, current, and fill factor resulted in efficiencies above 17%. The three project tasks and additional studies are described in detail in the final report. Most cells studied were fabricated at Colorado State using an industry-compatible single-vacuum closed-space-sublimation (CSS) chamber for deposition of the key semiconductor layers. Additionally, some cells were supplied by First Solar for comparison purposes, and a small number of modules were supplied by Abound Solar.

  12. Webinar January 13: Highly Efficient Solar Thermochemical Reaction...

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

    efficiency, converting methane and water into syngas-a mix of hydrogen and carbon monoxide-and the technology received an R&D 100 Award in 2014. As the solar energy is stored...

  13. Integrated Solar Thermochemical Reaction System for High Efficiency...

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

    This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held April 23-25, 2013 near Phoenix, Arizona. cspreviewmeeting042313wegeng.p...

  14. Conversion Tower for Dispatchable Solar Power: High-Efficiency Solar-Electric Conversion Power Tower

    SciTech Connect (OSTI)

    2012-01-11

    HEATS Project: Abengoa Solar is developing a high-efficiency solar-electric conversion tower to enable low-cost, fully dispatchable solar energy generation. Abengoa’s conversion tower utilizes new system architecture and a two-phase thermal energy storage media with an efficient supercritical carbon dioxide (CO2) power cycle. The company is using a high-temperature heat-transfer fluid with a phase change in between its hot and cold operating temperature. The fluid serves as a heat storage material and is cheaper and more efficient than conventional heat-storage materials, like molten salt. It also allows the use of a high heat flux solar receiver, advanced high thermal energy density storage, and more efficient power cycles.

  15. New approaches for high-efficiency solar cells. Final report

    SciTech Connect (OSTI)

    Bedair, S.M.; El-Masry, N.A.

    1997-12-01

    This report summarizes the activities carried out in this subcontract. These activities cover, first the atomic layer epitaxy (ALE) growth of GaAs, AlGaAs and InGaP at fairly low growth temperatures. This was followed by using ALE to achieve high levels of doping both n-type and p-type required for tunnel junctions (Tj) in the cascade solar cell structures. Then the authors studied the properties of AlGaAs/InGaP and AlGaAs/GaAs tunnel junctions and their performances at different growth conditions. This is followed by the use of these tunnel junctions in stacked solar cell structures. The effect of these tunnel junctions on the performance of stacked solar cells was studied at different temperatures and different solar fluences. Finally, the authors studied the effect of different types of black surface fields (BSF), both p/n and n/p GaInP solar cell structures, and their potential for window layer applications. Parts of these activities were carried in close cooperation with Dr. Mike Timmons of the Research Triangle Institute.

  16. High-efficiency solar cells using HEM silicon

    SciTech Connect (OSTI)

    Khattak, C.P.; Schmid, F.; Schubert, W.K.

    1994-12-31

    Developments in Heat Exchanger Method (HEM) technology for production of multicrystalline silicon ingot production have led to growth of larger ingots (55 cm square cross section) with lower costs and reliability in production. A single reusable crucible has been used to produce 18 multicrystalline 33 cm square cross section 40 kg ingots, and capability to produce 44 cm ingots has been demonstrated. Large area solar cells of 16.3% (42 cm{sup 2}) and 15.3% (100 cm{sup 2}) efficiency have been produced without optimization of the material production and the solar cell processing.

  17. High Efficiency CdTe Ink-Based Solar Cells Using Nanocrystals (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2015-01-01

    This NREL Highlight is being developed for the 2015 February Alliance S&T Board meeting and describes a solution-processable ink to produce high-efficiency solar cells using low temperature and simple processing.

  18. Design for the fabrication of high efficiency solar cells

    DOE Patents [OSTI]

    Simmons, Joseph H.

    1998-01-01

    A method and apparatus for a photo-active region for generation of free carriers when a first surface is exposed to optical radiation. The photo-active region includes a conducting transparent matrix and clusters of semiconductor materials embedded within the conducting transparent matrix. The clusters are arranged in the matrix material so as to define at least a first distribution of cluster sizes ranging from those with the highest bandgap energy near a light incident surface of the photo-active region to those with the smallest bandgap energy near an opposite second surface of the photo-active region. Also disclosed is a method and apparatus for a solar cell. The solar cell includes a photo-active region containing a plurality of semiconductor clusters of varying sizes as described.

  19. Approach towards high efficiency polycrystalline silicon solar cells

    SciTech Connect (OSTI)

    Rohatgi, A.; Sana, P.; Chen, Z.; Salami, J. )

    1992-12-01

    A combination of theoretical modelling, gettering and passivation, and cell fabrication is presented in this paper to provide guidelines for improving efficiency of polycrystalline solar cells. Theoretical modelling was performed to show that grain boundary barrier height decreases and carrier diffusion length increases with illumination level ([le]50 suns) in those polycrystalline materials where grain boundary dominates the recombination. Model calculations show that the efficiency spread due to grain boundary defect density ([ital N][sub [ital st

  20. High-Efficiency Low-Cost Solar Receiver for Use in a Supercritical CO2

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

    Recompression Cycle | Department of Energy Low-Cost Solar Receiver for Use in a Supercritical CO2 Recompression Cycle High-Efficiency Low-Cost Solar Receiver for Use in a Supercritical CO2 Recompression Cycle This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held April 23-25, 2013 near Phoenix, Arizona. csp_review_meeting_042313_sullivan.pdf (1.45 MB) More Documents & Publications High-Efficiency Low-Cost Solar Receiver for Use in a

  1. Advanced Nanomaterials for High-Efficiency Solar Cells

    SciTech Connect (OSTI)

    Chen, Junhong

    2013-11-29

    Energy supply has arguably become one of the most important problems facing humankind. The exponential demand for energy is evidenced by dwindling fossil fuel supplies and record-high oil and gas prices due to global population growth and economic development. This energy shortage has significant implications to the future of our society, in addition to the greenhouse gas emission burden due to consumption of fossil fuels. Solar energy seems to be the most viable choice to meet our clean energy demand given its large scale and clean/renewable nature. However, existing methods to convert sun light into electricity are not efficient enough to become a practical alternative to fossil fuels. This DOE project aims to develop advanced hybrid nanomaterials consisting of semiconductor nanoparticles (quantum dots or QDs) supported on graphene for cost-effective solar cells with improved conversion efficiency for harvesting abundant, renewable, clean solar energy to relieve our global energy challenge. Expected outcomes of the project include new methods for low-cost manufacturing of hybrid nanostructures, systematic understanding of their properties that can be tailored for desired applications, and novel photovoltaic cells. Through this project, we have successfully synthesized a number of novel nanomaterials, including vertically-oriented graphene (VG) sheets, three-dimensional (3D) carbon nanostructures comprising few-layer graphene (FLG) sheets inherently connected with CNTs through sp{sup 2} carbons, crumpled graphene (CG)-nanocrystal hybrids, CdSe nanoparticles (NPs), CdS NPs, nanohybrids of metal nitride decorated on nitrogen-doped graphene (NG), QD-carbon nanotube (CNT) and QD-VG-CNT structures, TiO{sub 2}-CdS NPs, and reduced graphene oxide (RGO)-SnO{sub 2} NPs. We further assembled CdSe NPs onto graphene sheets and investigated physical and electronic interactions between CdSe NPs and the graphene. Finally we have demonstrated various applications of these

  2. Graphene Oxide Interlayers for Robust, High-Efficiency Organic Photovoltaics

    SciTech Connect (OSTI)

    Murray, Ian P.; Lou, Sylvia J.; Cote, Laura J.; Loser, Stephen; Kadleck, Cameron J.; Xu, Tao; Szarko, Jodi M.; Rolczynski, Brian S.; Johns, James E.; Huang, Jiaxing; Yu, Luping; Chen, Lin X.; Marks, Tobin J.; Hersam, Mark C.

    2012-02-07

    Organic photovoltaic (OPV) materials have recently garnered significant attention as enablers of high power conversion efficiency (PCE), low-cost, mechanically flexible solar cells. Nevertheless, further understanding-based materials developments will be required to achieve full commercial viability. In particular, the performance and durability of many current generation OPVs are limited by poorly understood interfacial phenomena. Careful analysis of typical OPV architectures reveals that the standard electron-blocking layer, poly-3,4-ethylenedioxy-thiophene:poly(styrene sulfonate) (PEDOT:PSS), is likely a major factor limiting the device durability and possibly performance. Here we report that a single layer of electronically tuned graphene oxide is an effective replacement for PEDOT:PSS and that it significantly enhances device durability while concurrently templating a performance-optimal active layer {pi}-stacked face-on microstructure. Such OPVs based on graphene oxide exhibit PCEs as high as 7.5% while providing a 5x enhancement in thermal aging lifetime and a 20x enhancement in humid ambient lifetime versus analogous PEDOT:PSS-based devices.

  3. Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation

    SciTech Connect (OSTI)

    Hanna, M. C.; Ellingson, R. J.; Beard, M.; Yu, P.; Micic, O. I.; Nozik, A. J.; c.

    2005-01-01

    Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this effect produces greatly enhanced theoretical thermodynamic conversion efficiencies that range from 45-85%, depending upon solar concentration, the cell temperature, and the number of electron-hole pairs produced per photon. For quantum dots (QDs), electron-hole pairs exist as excitons. We have observed astoundingly efficient multiple exciton generation (MEG) in QDs of PbSe (bulk Eg = 0.28 eV), ranging in diameter from 3.9 to 5.7nm (Eg = 0.73, 0.82, and 0.91 eV, respectively). The effective masses of electron and holes are about equal in PbSe, and the onset for efficient MEG occurs at about three times the QD HOMO-LUMO transition (its ''bandgap''). The quantum yield rises quickly after the onset and reaches 300% at 4 x Eg (3.64 eV) for the smallest QD; this means that every QD in the sample produces three electron-hole pairs/photon.

  4. High-Efficiency Solar Cells for Large-Scale Electricity Generation

    SciTech Connect (OSTI)

    Kurtz, S.; Olson, J.; Geisz, J.; Friedman, D.; McMahon, W.; Ptak, A.; Wanlass, M.; Kibbler, A.; Kramer, C.; Bertness, K.; Ward, S.; Duda, A.; Young, M.; Carapella, J.; Steiner, M.

    2008-09-26

    One strategy for helping the solar industry to grow faster is to use very high efficiency cells under concentrating optics. By using lenses or mirrors to concentrate the light, very small solar cells can be used, reducing the amount of semiconductor material and allowing use of higher efficiency cells, which are now >40% efficient.

  5. Light Trapping for High Efficiency Heterojunction Crystalline Si Solar Cells: Preprint

    SciTech Connect (OSTI)

    Wang, Q.; Xu, Y.; Iwaniczko, E.; Page, M.

    2011-04-01

    Light trapping plays an important role to achieve high short circuit current density (Jsc) and high efficiency for amorphous/crystalline Si heterojunction solar cells. Si heterojunction uses hydrogenated amorphous Si for emitter and back contact. This structure of solar cell posses highest open circuit voltage of 0.747 V at one sun for c-Si based solar cells. It also suggests that over 25% record-high efficiency is possible with further improvement of Jsc. Light trapping has two important tasks. The first one is to reduce the surface reflectance of light to zero for the solar spectrum that Si has a response. The second one is to increase the effective absorption length to capture all the photon. For Si heterojunction solar cell, surface texturing, anti-reflectance indium tin oxides (ITO) layer at the front and back are the key area to improve the light trapping.

  6. Fundamental understanding and development of low-cost, high-efficiency silicon solar cells

    SciTech Connect (OSTI)

    ROHATGI,A.; NARASIMHA,S.; MOSCHER,J.; EBONG,A.; KAMRA,S.; KRYGOWSKI,T.; DOSHI,P.; RISTOW,A.; YELUNDUR,V.; RUBY,DOUGLAS S.

    2000-05-01

    The overall objectives of this program are (1) to develop rapid and low-cost processes for manufacturing that can improve yield, throughput, and performance of silicon photovoltaic devices, (2) to design and fabricate high-efficiency solar cells on promising low-cost materials, and (3) to improve the fundamental understanding of advanced photovoltaic devices. Several rapid and potentially low-cost technologies are described in this report that were developed and applied toward the fabrication of high-efficiency silicon solar cells.

  7. Project Profile: High-Efficiency Thermal Storage System for Solar Plants |

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

    Department of Energy Thermal Storage System for Solar Plants Project Profile: High-Efficiency Thermal Storage System for Solar Plants SENER logo SENER, under the Baseload CSP FOA, aimed to develop a highly efficient, low-maintenance and economical thermal energy storage (TES) system using solid graphite modular blocks for CSP plants. Approach Graphic of a rectangle shape to the left of a row or smaller rectangles stacked in two rows. The main objective was to evaluate a TES system able to

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

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

    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 Lead Performer: ...

  9. Phosphorescent organic light emitting diodes with high efficiency and brightness

    DOE Patents [OSTI]

    Forrest, Stephen R; Zhang, Yifan

    2015-11-12

    An organic light emitting device including a) an anode; b) a cathode; and c) an emissive layer disposed between the anode and the cathode, the emissive layer comprising an organic host compound and a phosphorescent compound exhibiting a Stokes Shift overlap greater than 0.3 eV. The organic light emitting device may further include a hole transport layer disposed between the emissive layer and the anode; and an electron transport layer disposed between the emissive layer and the cathode. In some embodiments, the phosphorescent compound exhibits a phosphorescent lifetime of less than 10 .mu.s. In some embodiments, the concentration of the phosphorescent compound ranges from 0.5 wt. % to 10 wt. %.

  10. High-Efficiency Solar Cogeneration with Thermophotovoltaic & Fiber-Optic

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

    Daylighting | Department of Energy Efficiency Solar Cogeneration with Thermophotovoltaic & Fiber-Optic Daylighting High-Efficiency Solar Cogeneration with Thermophotovoltaic & Fiber-Optic Daylighting Credit: Creative Light Source, Inc. Credit: Creative Light Source, Inc. Lead Performer: Creative Light Source, Inc. DOE Funding: $1,724,521 (total for SBIR Phases I and 2) Cost Share: N/A Project Term: 7/28/14 - 7/28/16 Funding Opportunity Announcement: 2013 - Small Business Innovation

  11. High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

    SciTech Connect (OSTI)

    Antoniadis, H.

    2011-03-01

    Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

  12. New concepts for high efficiency energy conversion: The avalanche heterostructure and superlattice solar cells

    SciTech Connect (OSTI)

    Summers, C.J.; Rohatgi, A.; Torabi, A.; Harris, H.M. )

    1993-01-01

    This report describes investigation into the theory and technology of a novel heterojunction or superlattice, single-junction solar cell, which injects electrons across the heterointerface to produce highly efficient impact ionization of carriers in the lowband-gap side of the junction, thereby conserving their total energy. Also, the superlattice structure has the advantage of relaxing the need for perfect lattice matching at the p-n interface and will inhibit the cross diffusion of dopant atoms that typically occurs in heavy doping. This structure avoids the use of tunnel junctions that make it very difficult to achieve the predicted efficiencies in cascade cells, thus making it possible to obtain energy efficiencies that are competitive with those predicted for cascade solar cells with reduced complexity and cost. This cell structure could also be incorporated into other solar cell structures designed for wider spectral coverage.

  13. Numerical analysis for high-efficiency GaAs solar cells fabricated on Si substrates

    SciTech Connect (OSTI)

    Yamaguchi, M.; Amano, C.; Itoh, Y.

    1989-07-15

    This paper describes some recent developments in GaAs thin-film solar cells fabricated on Si substrates by metalorganic chemical vapor deposition and numerically analyzes them.GaAs solar cells with efficiency of more than 18% are successfully fabricated on Si substrates by reducing the dislocation density. Photovoltaic properties of GaAs/Si cells are analyzed by considering the effect of nonuniform dislocation distribution on recombination properties of GaAs thin films on Si substrates. Numerical analysis shows that the effect of majority-carrier trapping must be considered. High efficiency GaAs solar cells with total-area efficiency of over 20% on Si substrates can be realized if dislocation density can be reduced to less than 5/times/10/sup 5/ cm/sup /minus/2/.

  14. High-Efficiency Solar Cogeneration with T-PV and Fiber Optic Daylighting

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

    DiMasi joseph@CreativeLightSource.com Creative Light Source, inc. High-Efficiency Solar Cogeneration with T-PV and Fiber Optic Daylighting 2015 Building Technologies Office Peer Review ‹#› Project Summary Timeline: Start date: August, 2014 Planned end date: July, 2016 Key Milestones: 1. Y1 prototype test-bed functional; 7/15 2. Full IR-PV cogeneration system; 3/16 3. Building Trials at customer facility; 6/16 Budget: Total DOE $ to date: $975,000 (P1 + P2, Y1) Total future DOE $: $750,000

  15. CdTe portfolio offers commercial ready high efficiency solar - Energy

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

    Innovation Portal Find More Like This Return to Search CdTe portfolio offers commercial ready high efficiency solar National Renewable Energy Laboratory Contact NREL About This Technology Publications: PDF Document Publication MktgSummary CdTe.pdf (117 KB) Schematic illustration of a typical CdTe superstrate thin-film PV device. In this design, the layers of the device are deposited onto a glass &quot;superstrate&quot; that allows sunlight to enter. The sunlight passes through the

  16. High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrator Application

    SciTech Connect (OSTI)

    Hubbard, Seth

    2012-09-12

    The High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrators project seeks to provide new photovoltaic cells for Concentrator Photovoltaics (CPV) Systems with higher cell efficiency, more favorable temperature coefficients and less sensitivity to changes in spectral distribution. The main objective of this project is to provide high efficiency III-V solar cells that will reduce the overall cost per Watt for power generation using CPV systems.This work is focused both on a potential near term application, namely the use of indium arsenide (InAs) QDs to spectrally "tune" the middle (GaAs) cell of a SOA triple junction device to a more favorable effective bandgap, as well as the long term goal of demonstrating intermediate band solar cell effects. The QDs are confined within a high electric field i-region of a standard GaAs solar cell. The extended absorption spectrum (and thus enhanced short circuit current) of the QD solar cell results from the increase in the sub GaAs bandgap spectral response that is achievable as quantum dot layers are introduced into the i-region. We have grown InAs quantum dots by OMVPE technique and optimized the QD growth conditions. Arrays of up to 40 layers of strain balanced quantum dots have been experimentally demonstrated with good material quality, low residual stain and high PL intensity. Quantum dot enhanced solar cells were grown and tested under simulated one sun AM1.5 conditions. Concentrator solar cells have been grown and fabricated with 5-40 layers of QDs. Testing of these devices show the QD cells have improved efficiency compared to baseline devices without QDs. Device modeling and measurement of thermal properties were performed using Crosslight APSYS. Improvements in a triple junction solar cell with the insertion of QDs into the middle current limiting junction was shown to be as high as 29% under one sun illumination for a 10 layer stack QD enhanced triple junction solar cell. QD devices have strong

  17. The Importance of Domain Size and Purity in High-Efficiency Organic...

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

    Molecular view of a polymerorganic solar film showing an interface between donor and acceptor domains. Red dots are organic fullerene molecules and blue lines represent polymer ...

  18. High-Efficiency and Stable White Organic Light-Emitting Diode Using a

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

    Single Emitter | Department of Energy and Stable White Organic Light-Emitting Diode Using a Single Emitter High-Efficiency and Stable White Organic Light-Emitting Diode Using a Single Emitter Lead Performer: Arizona State University - Tempe, AZ DOE Total Funding: $664,785 Cost Share: $170,547 Project Term: 10/1/2011 - 9/30/2015 Funding Opportunity: Solid State Lighting Core Technology Funding Opportunity Announcement (DE-FOA- 0000329) Project Objective This project will demonstrate an

  19. High efficiency and brightness fluorescent organic light emitting diode by triplet-triplet fusion

    DOE Patents [OSTI]

    Forrest, Stephen; Zhang, Yifan

    2015-02-10

    A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer may include an organic host compound and at least one organic emitting compound capable of fluorescent emission at room temperature. Various configurations are described for providing a range of current densities in which T-T fusion dominates over S-T annihilation, leading to very high efficiency fluorescent OLEDs.

  20. High-Efficiency GaInP/GaAs Tandem Solar Cells

    SciTech Connect (OSTI)

    Bertness, K. A.; Friedman, D. J.; Kurtz, S. R.; Kibbler, A. E.; Cramer, C.; Olson, J. M.

    1996-09-01

    GaInP/GaAs tandem solar cells have achieved efficiencies between 25.7-30.2%, depending on illumination conditions. The efficiencies are the highest confirmed two-terminal values measured for any solar cell within each standard illumination category. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance.

  1. High-efficiency GaInP/GaAs tandem solar cells

    SciTech Connect (OSTI)

    Bertness, K.A.; Friedman, D.J.; Kurtz, S.R.; Kibbler, A.E.; Kramer, C.; Olson, J.M.

    1994-12-01

    GaInP/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AM0) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance. 31 refs.

  2. Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

    SciTech Connect (OSTI)

    Martini, R.; Kepa, J.; Stesmans, A.; Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I.; Poortmans, J.

    2014-10-27

    We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process. A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.

  3. High-efficiency, flexible CdTe solar cells on ultra-thin glass substrates

    SciTech Connect (OSTI)

    Mahabaduge, H. P.; Rance, W. L.; Burst, J. M.; Reese, M. O.; Gessert, T. A.; Metzger, W. K.; Barnes, T. M.; Meysing, D. M.; Wolden, C. A.; Li, J.; Beach, J. D.; Garner, S.

    2015-03-30

    Flexible, high-efficiency, low-cost solar cells can enable applications that take advantage of high specific power, flexible form factors, lower installation and transportation costs. Here, we report a certified record efficiency of 16.4% for a flexible CdTe solar cell that is a marked improvement over the previous standard (14.05%). The improvement was achieved by replacing chemical-bath-deposited CdS with sputtered CdS:O and also replacing the high-temperature sputtered ZnTe:Cu back contact layer with co-evaporated and rapidly annealed ZnTe:Cu. We use quantum efficiency and capacitance-voltage measurements combined with device simulations to identify the reasons for the increase in efficiency. Both device simulations and experimental results show that higher carrier density can quantitatively account for the increased open circuit voltage (V{sub OC}) and Fill Factor (FF), and likewise, the increase in short circuit current density (J{sub SC}) can be attributed to the more transparent CdS:O.

  4. High temperature performance of high-efficiency, multi-layer solar selective coatings for tower applications

    SciTech Connect (OSTI)

    Gray, M. H.; Tirawat, R.; Kessinger, K. A.; Ndione, P. F.

    2015-05-01

    The roadmap to next-generation concentrating solar power plants anticipates a progression to central towers with operating temperatures in excess of 650C. These higher temperatures are required to drive higher power-cycle efficiencies, resulting in lower cost energy. However, these conditions also place a greater burden on the materials making up the receiver. Any novel absorber material developed for next-generation receivers must be stable in air, cost effective, and survive thousands of heating and cooling cycles. The collection efficiency of a power tower plant can be increased if the energy absorbed by the receiver is maximized while the heat loss from the receiver to the environment is minimized. Thermal radiation losses can be significant (>7% annual energy loss) with receivers at temperatures above 650C. We present progress toward highly efficient and durable solar selective absorbers (SSAs) intended for operating temperatures from 650C to 1000C. Selective efficiency (?sel) is defined as the energy retained by the absorber, accounting for both absorptance and emittance, relative to the energy incident on the surface. The low emittance layers of multilayer SSAs are binary compounds of refractory metals whose material properties indicate that coatings formed of these materials should be oxidation resistant in air to 800-1200C. On this basis, we initially developed a solar selective coating for parabolic troughs. This development has been successfully extended to meet the absorptance and emittance objectives for the more demanding, high temperature regime. We show advancement in coating materials, processing and designs resulting in the initial attainment of target efficiencies ?sel > 0.91 for proposed tower conditions. Additionally, spectral measurements show that these coatings continue to perform at targeted levels after cycling to temperatures of 1000C in environments of nitrogen and forming gas.

  5. High temperature performance of high-efficiency, multi-layer solar selective coatings for tower applications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gray, M. H.; Tirawat, R.; Kessinger, K. A.; Ndione, P. F.

    2015-05-01

    The roadmap to next-generation concentrating solar power plants anticipates a progression to central towers with operating temperatures in excess of 650°C. These higher temperatures are required to drive higher power-cycle efficiencies, resulting in lower cost energy. However, these conditions also place a greater burden on the materials making up the receiver. Any novel absorber material developed for next-generation receivers must be stable in air, cost effective, and survive thousands of heating and cooling cycles. The collection efficiency of a power tower plant can be increased if the energy absorbed by the receiver is maximized while the heat loss from themore » receiver to the environment is minimized. Thermal radiation losses can be significant (>7% annual energy loss) with receivers at temperatures above 650°C. We present progress toward highly efficient and durable solar selective absorbers (SSAs) intended for operating temperatures from 650°C to 1000°C. Selective efficiency (ηsel) is defined as the energy retained by the absorber, accounting for both absorptance and emittance, relative to the energy incident on the surface. The low emittance layers of multilayer SSAs are binary compounds of refractory metals whose material properties indicate that coatings formed of these materials should be oxidation resistant in air to 800-1200°C. On this basis, we initially developed a solar selective coating for parabolic troughs. This development has been successfully extended to meet the absorptance and emittance objectives for the more demanding, high temperature regime. We show advancement in coating materials, processing and designs resulting in the initial attainment of target efficiencies ηsel > 0.91 for proposed tower conditions. Additionally, spectral measurements show that these coatings continue to perform at targeted levels after cycling to temperatures of 1000°C in environments of nitrogen and forming gas.« less

  6. High Efficiency Single Crystal CdTe Solar Cells: November 19, 2009 - January 31, 2011

    SciTech Connect (OSTI)

    Carmody, M.; Gilmore, A.

    2011-05-01

    The goal of the program was to develop single crystal CdTe-based top cells grown on Si solar cells as a platform for the subsequent manufacture of high efficiency tandem cells for CPV applications. The keys to both the single junction and the tandem junction cell architectures are the ability to grow high quality single-crystal CdTe and CdZnTe layers on p-type Si substrates, to dope the CdTe and CdZnTe controllably, both n and p-type, and to make low resistance ohmic front and back contacts. EPIR demonstrated the consistent MBE growth of CdTe/Si and CdZnTe/Si having high crystalline quality despite very large lattice mismatches; epitaxial CdTe/Si and CdZnTe/Si consistently showed state-of-the-art electron mobilities and good hole mobilities; bulk minority carrier recombination lifetimes of unintentionally p-doped CdTe and CdZnTe grown by MBE on Si were demonstrated to be consistently of order 100 ns or longer; desired n- and p-doping levels were achieved; solar cell series specific resistances <10 ?-cm2 were achieved; A single-junction solar cell having a state-of-the-art value of Voc and a unverified 16.4% efficiency was fabricated from CdZnTe having a 1.80 eV bandgap, ideal for the top junction in a tandem cell with a Si bottom junction.

  7. High temperature performance of high-efficiency, multi-layer solar selective coatings for tower applications

    SciTech Connect (OSTI)

    Gray, M. H.; Tirawat, R.; Kessinger, K. A.; Ndione, P. F.

    2015-05-01

    The roadmap to next-generation concentrating solar power plants anticipates a progression to central towers with operating temperatures in excess of 650°C. These higher temperatures are required to drive higher power-cycle efficiencies, resulting in lower cost energy. However, these conditions also place a greater burden on the materials making up the receiver. Any novel absorber material developed for next-generation receivers must be stable in air, cost effective, and survive thousands of heating and cooling cycles. The collection efficiency of a power tower plant can be increased if the energy absorbed by the receiver is maximized while the heat loss from the receiver to the environment is minimized. Thermal radiation losses can be significant (>7% annual energy loss) with receivers at temperatures above 650°C. We present progress toward highly efficient and durable solar selective absorbers (SSAs) intended for operating temperatures from 650°C to 1000°C. Selective efficiency (ηsel) is defined as the energy retained by the absorber, accounting for both absorptance and emittance, relative to the energy incident on the surface. The low emittance layers of multilayer SSAs are binary compounds of refractory metals whose material properties indicate that coatings formed of these materials should be oxidation resistant in air to 800-1200°C. On this basis, we initially developed a solar selective coating for parabolic troughs. This development has been successfully extended to meet the absorptance and emittance objectives for the more demanding, high temperature regime. We show advancement in coating materials, processing and designs resulting in the initial attainment of target efficiencies ηsel > 0.91 for proposed tower conditions. Additionally, spectral measurements show that these coatings continue to perform at targeted levels after cycling to temperatures of 1000°C in environments of nitrogen and forming gas.

  8. Turning Bacteria into Fuel: Cyanobacteria Designed for Solar-Powered Highly Efficient Production of Biofuels

    SciTech Connect (OSTI)

    2010-01-01

    Broad Funding Opportunity Announcement Project: ASU is engineering a type of photosynthetic bacteria that efficiently produce fatty acidsa fuel precursor for biofuels. This type of bacteria, called Synechocystis, is already good at converting solar energy and carbon dioxide (CO2) into a type of fatty acid called lauric acid. ASU has modified the organism so it continuously converts sunlight and CO2 into fatty acidsoverriding its natural tendency to use solar energy solely for cell growth and maximizing the solar-to-fuel conversion process. ASUs approach is different because most biofuels research focuses on increasing cellular biomass and not on excreting fatty acids. The project has also identified a unique way to convert the harvested lauric acid into a fuel that can be easily blended with existing transportation fuels.

  9. High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence

    SciTech Connect (OSTI)

    Nishide, Jun-ichi; Hiraga, Yasuhide; Nakanotani, Hajime; Adachi, Chihaya

    2014-06-09

    White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).

  10. High Efficiency CdTe and CIGS Thin Film Solar Cells: Highlights...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 14 SOLAR ENERGY; 36 MATERIALS SCIENCE; EFFICIENCY; ENERGY CONVERSION; SOLAR CELLS; THIN FILMS ...

  11. High mobility high efficiency organic films based on pure organic materials

    DOE Patents [OSTI]

    Salzman, Rhonda F.; Forrest, Stephen R.

    2009-01-27

    A method of purifying small molecule organic material, performed as a series of operations beginning with a first sample of the organic small molecule material. The first step is to purify the organic small molecule material by thermal gradient sublimation. The second step is to test the purity of at least one sample from the purified organic small molecule material by spectroscopy. The third step is to repeat the first through third steps on the purified small molecule material if the spectroscopic testing reveals any peaks exceeding a threshold percentage of a magnitude of a characteristic peak of a target organic small molecule. The steps are performed at least twice. The threshold percentage is at most 10%. Preferably the threshold percentage is 5% and more preferably 2%. The threshold percentage may be selected based on the spectra of past samples that achieved target performance characteristics in finished devices.

  12. Novel Low Cost Organic Vapor Jet Printing of Striped High Efficiency Phosphorescent OLEDs for White Lighting

    SciTech Connect (OSTI)

    Mike Hack

    2008-12-31

    In this program, Universal Display Corporation and University of Michigan proposed to integrate three innovative concepts to meet the DOE's Solid State Lighting (SSL) goals: (1) high-efficiency phosphorescent organic light emitting device (PHOLED{trademark}) technology, (2) a white lighting design that is based on a series of red, green and blue OLED stripes, and (3) the use of a novel cost-effective, high rate, mask-less deposition process called organic vapor jet printing (OVJP). Our PHOLED technology offers up to four-times higher power efficiency than other OLED approaches for general lighting. We believe that one of the most promising approaches to maximizing the efficiency of OLED lighting sources is to produce stripes of the three primary colors at such a pitch (200-500 {mu}m) that they appear as a uniform white light to an observer greater than 1 meter (m) away from the illumination source. Earlier work from a SBIR Phase 1 entitled 'White Illumination Sources Using Striped Phosphorescent OLEDs' suggests that stripe widths of less than 500 {mu}m appear uniform from a distance of 1m without the need for an external diffuser. In this program, we intend to combine continued advances in this PHOLED technology with the striped RGB lighting design to demonstrate a high-efficiency, white lighting source. Using this background technology, the team has focused on developing and demonstrating the novel cost-effective OVJP process to fabricate these high-efficiency white PHOLED light sources. Because this groundbreaking OVJP process is a direct printing approach that enables the OLED stripes to be printed without a shadow mask, OVJP offers very high material utilization and high throughput without the costs and wastage associated with a shadow mask (i.e. the waste of material that deposits on the shadow mask itself). As a direct printing technique, OVJP also has the potential to offer ultra-high deposition rates (> 1,000 Angstroms/second) for any size or shaped

  13. The operation mechanism of poly(9,9-dioctylfluorenyl-2,7-diyl) dots in high efficiency polymer solar cells

    SciTech Connect (OSTI)

    Liu, Chunyu; He, Yeyuan; Zhang, Xinyuan; Li, Zhiqi; Li, Jinfeng; Zhang, Zhihui; Guo, Wenbin Ruan, Shengping; Shen, Liang

    2015-05-11

    The highly efficient polymer solar cells were realized by doping poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into active layer. The dependence of doping amount on devices performance was investigated and a high efficiency of 7.15% was obtained at an optimal concentration, accounting for a 22.4% enhancement. The incorporation of PFO dots (Pdots) is conducted to the improvement of J{sub sc} and fill factor mainly due to the enhancement of light absorption and charge transport property. Pdots blended in active layer provides an interface for charge transfer and enables the formation of percolation pathways for electron transport. The introduction of Pdots was proven an effective way to improve optical and electrical properties of solar cells.

  14. High throughput parallel backside contacting and periodic texturing for high-efficiency solar cells

    DOE Patents [OSTI]

    Daniel, Claus; Blue, Craig A.; Ott, Ronald D.

    2014-08-19

    Disclosed are configurations of long-range ordered features of solar cell materials, and methods for forming same. Some features include electrical access openings through a backing layer to a photovoltaic material in the solar cell. Some features include textured features disposed adjacent a surface of a solar cell material. Typically the long-range ordered features are formed by ablating the solar cell material with a laser interference pattern from at least two laser beams.

  15. The effects of concentrated ultraviolet light on high-efficiency silicon solar cells

    SciTech Connect (OSTI)

    Ruby, D.S.; Schubert, W.K.

    1991-01-01

    The importance of stability in the performance of solar cells is clearly recognized as fundamental. Some of the highest efficiency silicon solar cells demonstrated to date, such as the Point Contact solar cell and the Passivated Emitter solar cell, rely upon the passivation of cell surfaces in order to minimize recombination, which reduces cell power output. Recently, it has been shown that exposure to ultraviolet (UV) light of wavelengths present in the terrestrial solar spectrum can damage a passivating silicon-oxide interface and increase recombination. In this study, we compared the performance of Point Contact and Passivated Emitter solar cells after exposure to UV light. We also examined the effect of UV exposure on oxide-passivated silicon wafers. We found that current Passivated Emitter designs are stable at both one-sun and under concentrated sunlight. The evolution of Point Contact concentrator cell performance shows a clear trend towards more stable cells. 15 refs., 18 figs.

  16. NREL Produces Highly Efficient, Wide-Bandgap, Thin-Film Solar Cells (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-09-01

    Researchers at the National Renewable Energy Laboratory (NREL) are finding new ways to manufacture thin-film solar cells made from copper, indium, gallium, and selenium - called CIGS cells - that are different than conventional CIGS solar cells. Their use of high-temperature glass, designed by SCHOTT AG, allows higher fabrication temperatures, opening the door to new CIGS solar cells employing light-absorbing materials with wide 'bandgaps.'

  17. Development of Highly-Efficient GaInP/Si Tandem Solar Cells ...

    Office of Scientific and Technical Information (OSTI)

    Research Org: NREL (National Renewable Energy Laboratory (NREL), Golden, CO (United States)) Sponsoring Org: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar ...

  18. High efficiency thermal storage system for solar plants (HELSOLAR). Final report

    SciTech Connect (OSTI)

    Villarroel, Eduardo; Fernandez-Pello, Carlos; Lenartz, Jeff; Parysek, Karen

    2013-02-27

    The project objective was to develop a high temperature Thermal Storage System (TES) based on graphite and able to provide both economical and technical advantages with respect to existing solutions contributing to increase the share of Concentrated Solar Plants (CSP). One of the main disadvantages of most of the renewable energy systems is their dependence to instantaneous irradiation and, thus, lack of predictability. CSP plants with thermal storage have proved to offer a good solution to this problem although still at an elevated price. The identification of alternative concepts able to work more efficiently would help to speed up the convergence of CSP towards grid parity. One way to reduce costs is to work in a range of temperatures higher than those allowed by the actual molten salt systems, currently the benchmark for TES in CSP. This requires the use of alternative energy storage materials such as graphite, as well as the utilization of Heat Transfer Fluids (HTF) other than molten salts or organic oils. The main technical challenges identified are derived from the high temperatures and significant high pressures, which pose risks such as potential graphite and insulation oxidation, creep, fatigue, corrosion and stress-corrosion in the pipes, leakages in the joints, high blower drivers’ electrical power consumption, thermal compatibility or relative deformations of the different materials. At the end, the main challenge of the project, is to identify a technical solution able to overcome all these problems but still at a competitive cost when compared to already existing thermal storage solutions. Special attention is given to all these issues during this project.

  19. Multi-scale framework for the accelerated design of high-efficiency...

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

    Multi-scale framework for the accelerated design of high-efficiency organic photovoltaic cells Organic and hybrid organicinorganic solar cells (OSC) offer a promising low-cost...

  20. Incorporating photon recycling into the analytical drift-diffusion model of high efficiency solar cells

    SciTech Connect (OSTI)

    Lumb, Matthew P.; Steiner, Myles A.; Geisz, John F.; Walters, Robert J.

    2014-11-21

    The analytical drift-diffusion formalism is able to accurately simulate a wide range of solar cell architectures and was recently extended to include those with back surface reflectors. However, as solar cells approach the limits of material quality, photon recycling effects become increasingly important in predicting the behavior of these cells. In particular, the minority carrier diffusion length is significantly affected by the photon recycling, with consequences for the solar cell performance. In this paper, we outline an approach to account for photon recycling in the analytical Hovel model and compare analytical model predictions to GaAs-based experimental devices operating close to the fundamental efficiency limit.

  1. Silicon Ink for High-Efficiency Solar Cells Captures a Share of the Market (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-08-01

    Fact sheet on 2011 R&D 100 Award winner Silicon Ink. Liquid silicon has arrived, and with it comes a power boost for solar cells and dramatic cost savings for cell manufacturers.

  2. Numerical simulation: Toward the design of high-efficiency planar perovskite solar cells

    SciTech Connect (OSTI)

    Liu, Feng; Zhu, Jun E-mail: sydai@ipp.ac.cn; Wei, Junfeng; Li, Yi; Lv, Mei; Yang, Shangfeng; Zhang, Bing; Yao, Jianxi; Dai, Songyuan E-mail: sydai@ipp.ac.cn

    2014-06-23

    Organo-metal halide perovskite solar cells based on planar architecture have been reported to achieve remarkably high power conversion efficiency (PCE, >16%), rendering them highly competitive to the conventional silicon based solar cells. A thorough understanding of the role of each component in solar cells and their effects as a whole is still required for further improvement in PCE. In this work, the planar heterojunction-based perovskite solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D. Simulation results revealed a great dependence of PCE on the thickness and defect density of the perovskite layer. Meanwhile, parameters including the work function of the back contact as well as the hole mobility and acceptor density in hole transport materials were identified to significantly influence the performance of the device. Strikingly, an efficiency over 20% was obtained under the moderate simulation conditions.

  3. Stable, high-efficiency amorphous silicon solar cells with low hydrogen content

    SciTech Connect (OSTI)

    Fortmann, C.M.; Hegedus, S.S. )

    1992-12-01

    Results and conclusions obtained during a research program of the investigation of amorphous silicon and amorphous silicon based alloy materials and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

  4. Tandem Microwire Solar Cells for Flexible High Efficiency Low Cost Photovoltaics

    SciTech Connect (OSTI)

    Atwater, Harry A.

    2015-03-10

    , lattice-mismatched growth of a GaAs segment that extrude out of a Si wire via a self-aligned SiO2 hollow cylindrical mask. With this growth strategy, misfit dislocations that would normally form at the GaAs/Si interface during thin film epitaxy may bend over to and thus terminate at the sidewall of the SiO2 tube. A reactive-ion etching technique was employed 1) to remove Si to form a hollow, self-aligned SiO2 cylindrical tube as a growth template for GaAs epitaxy using a vertical, showerhead, low-pressure metal-organic chemical-vapor deposition reactor that was operated at 0.1 atm. Successful epitaxy of axial GaAs wires on non-polar, <111>-oriented Si wire substrates was found at temperatures of ~850C. This and the other III-V/Si heterojunction wire synthesis strategies described here are promising approaches to realize future III-V/Si tandem solar cell designs.

  5. InGaAsN: A Novel Material for High-Efficiency Solar Cells and Advanced Photonic Devices

    SciTech Connect (OSTI)

    Allerman, Andrew A.; Follstaedt, David M.; Gee, James M.; Jones, Eric D.; Kurtz, Steven R.; Modine, Norman A.

    1999-07-01

    This report represents the completion of a 6 month Laboratory-Directed Research and Development (LDRD) program that focused on research and development of novel compound semiconductor, InGaAsN. This project seeks to rapidly assess the potential of InGaAsN for improved high-efficiency photovoltaic. Due to the short time scale, the project focused on quickly investigating the range of attainable compositions and bandgaps while identifying possible material limitations for photovoltaic devices. InGaAsN is a new semiconductor alloy system with the remarkable property that the inclusion of only 2% nitrogen reduces the bandgap by more than 30%. In order to help understand the physical origin of this extreme deviation from the typically observed nearly linear dependence of alloy properties on concentration, we have investigated the pressure dependence of the excited state energies using both experimental and theoretical methods. We report measurements of the low temperature photoluminescence energy of the material for pressures between ambient and 110 kbar. We describe a simple, density-functional-theory-based approach to calculating the pressure dependence of low lying excitation energies for low concentration alloys. The theoretically predicted pressure dependence of the bandgap is in excellent agreement with the experimental data. Based on the results of our calculations, we suggest an explanation for the strongly non-linear pressure dependence of the bandgap that, surprisingly, does not involve a nitrogen impurity band. Additionally, conduction-band mass measurements, measured by three different techniques, will be described and finally, the magnetoluminescence determined pressure coefficient for the conduction-band mass is measured. The design, growth by metal-organic chemical vapor deposition, and processing of an In{sub 0.07}Ga{sub 0.93}As{sub 0.98}N{sub 0.02} solar cell, with 1.0 eV bandgap, lattice matched to GaAs is described. The hole diffusion length in

  6. Novel wide band gap materials for highly efficient thin film tandem solar cells

    SciTech Connect (OSTI)

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PVâ??s goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a

  7. High Efficiency Generation of Hydrogen Fuels Using Solar Thermochemical Splitting of Water

    SciTech Connect (OSTI)

    Heske, Clemens; Moujaes, Samir; Weimer, Alan; Wong, Bunsen; Siegal, Nathan; McFarland, Eric; Miller, Eric; Lewis, Michele; Bingham, Carl; Roth, Kurth; Sabacky, Bruce; Steinfeld, Aldo

    2011-09-29

    The objective of this work is to identify economically feasible concepts for the production of hydrogen from water using solar energy. The ultimate project objective was to select one or more competitive concepts for pilot-scale demonstration using concentrated solar energy. Results of pilot scale plant performance would be used as foundation for seeking public and private resources for full-scale plant development and testing. Economical success in this venture would afford the public with a renewable and limitless source of energy carrier for use in electric power load-leveling and as a carbon-free transportation fuel. The Solar Hydrogen Generation Research (SHGR) project embraces technologies relevant to hydrogen research under the Office of Hydrogen Fuel Cells and Infrastructure Technology (HFCIT) as well as concentrated solar power under the Office of Solar Energy Technologies (SET). Although the photoelectrochemical work is aligned with HFCIT, some of the technologies in this effort are also consistent with the skills and technologies found in concentrated solar power and photovoltaic technology under the Office of Solar Energy Technologies (SET). Hydrogen production by thermo-chemical water-splitting is a chemical process that accomplishes the decomposition of water into hydrogen and oxygen using only heat or a combination of heat and electrolysis instead of pure electrolysis and meets the goals for hydrogen production using only water and renewable solar energy as feed-stocks. Photoelectrochemical hydrogen production also meets these goals by implementing photo-electrolysis at the surface of a semiconductor in contact with an electrolyte with bias provided by a photovoltaic source. Here, water splitting is a photo-electrolytic process in which hydrogen is produced using only solar photons and water as feed-stocks. The thermochemical hydrogen task engendered formal collaborations among two universities, three national laboratories and two private sector

  8. III-V-N materials for super high-efficiency multijunction solar cells

    SciTech Connect (OSTI)

    Yamaguchi, Masafumi; Bouzazi, Boussairi; Suzuki, Hidetoshi; Ikeda, Kazuma; Kojima, Nobuaki; Ohshita, Yoshio

    2012-10-06

    We have been studying concentrator multi-junction solar cells under Japanese Innovative Photovoltaic R and D program since FY2008. InGaAsN is one of appropriate materials for 4-or 5-junction solar cell configuration because this material can be lattice-matched to GaAs and Ge substrates. However, present InGaAsN single-junction solar cells have been inefficient because of low minority-carrier lifetime due to N-related recombination centers and low carrier mobility due to alloy scattering and non-homogeneity of N. This paper presents our major results in the understanding of majority and minority carrier traps in GaAsN grown by chemical beam epitaxy and their relationships with the poor electrical properties of the materials.

  9. Development of Highly-Efficient GaInP/Si Tandem Solar Cells

    SciTech Connect (OSTI)

    Essig, Stephanie; Geisz, John F.; Steiner, Myles A.; Merkle, Agnes; Peibst, Robby; Schmidt, Jan; Brendel, Rolf; Ward, Scott; Friedman, Daniel J.; Stradins, Paul; Young, David L.

    2015-06-14

    Dual-junction solar cells consisting of rear-heterojunction GaInP top cells and back-junction, back-contacted crystalline Si bottom cells were fabricated and characterized. Our calculations show that theoretical efficiencies up to 38.9% can be achieved with Si-based tandem devices. In our experiments, the two subcells were fabricated separately and stacked with an index matching fluid. In contrast to conventional mechanically stacked solar cells, that contain two metal grids at the interface, our concept includes a fully back contacted bottom cell which reduces the shadow losses in the device. A 1-sun AM1.5g cumulative efficiency of (26.2 +/- 0.6)% has been achieved with this novel GaInP/Si 4-terminal tandem solar cell.

  10. High efficiency epitaxial optical reflector solar cells. Final subcontract report, 1 January 1990--31 October 1992

    SciTech Connect (OSTI)

    Dapkus, P.D.; Hummel, S.G.

    1993-08-01

    This report describes work to test the feasibility of a new solar cell concept -- the epitaxial optical reflector (EOR) solar cell. This cell concept alters current designs for high efficiency cells by changing the optical absorption efficiency of single cells. The change is introduced by the use an epitaxial multilayer reflector as an integral part of the cell to increase the optical path length of certain wavelengths of light in the cell. These changes are expected to increase the open circuit voltage at which power is extracted from the cell. The program is designed to test the feasibility of the use of a broad band epitaxial multilayer reflector grown as an integral part of the device structure to reflect the near-band-edge light back through the device for a second absorption pass. This second pass allows the design of a solar cell with a thinner base, and the use of the epitaxial reflector as a heterojunction carrier-reflecting barrier at the rear of the device. The thinner cell design and altered carrier profile that results from the light- and carrier-reflecting barrier will decrease the carrier concentration gradient and increase the open circuit voltage. The program is structured to have three tasks: (1) Solar Cell and Reflector Modeling, (2) Materials Growth and Optimization, and (3) Solar Cell Fabrication and Characterization.

  11. Highly efficient ultrathin-film amorphous silicon solar cells on top of imprinted periodic nanodot arrays

    SciTech Connect (OSTI)

    Yan, Wensheng Gu, Min; Tao, Zhikuo; Ong, Thiam Min Brian

    2015-03-02

    The addressing of the light absorption and conversion efficiency is critical to the ultrathin-film hydrogenated amorphous silicon (a-Si:H) solar cells. We systematically investigate ultrathin a-Si:H solar cells with a 100 nm absorber on top of imprinted hexagonal nanodot arrays. Experimental evidences are demonstrated for not only notable silver nanodot arrays but also lower-cost ITO and Al:ZnO nanodot arrays. The measured external quantum efficiency is explained by the simulation results. The J{sub sc} values are 12.1, 13.0, and 14.3 mA/cm{sup 2} and efficiencies are 6.6%, 7.5%, and 8.3% for ITO, Al:ZnO, and silver nanodot arrays, respectively. Simulated optical absorption distribution shows high light trapping within amorphous silicon layer.

  12. Device Architecture and Lifetime Requirements for High Efficiency Multicrystalline Silicon Solar Cells

    SciTech Connect (OSTI)

    Wagner, H.; Hofstetter, J.; Mitchell, B.; Altermatt, P.; Buonassisi, T.

    2015-03-23

    We present a numerical simulation study of different multicrystalline silicon materials and solar cell architectures to understand today's efficiency limitations and future efficiency possibilities. We compare conventional full-area BSF and PERC solar cells to future cell designs with a gallium phosphide heteroemitter. For all designs, mc-Si materials with different excess carrier lifetime distributions are used as simulation input parameters to capture a broad range of materials. The results show that conventional solar cell designs are sufficient for generalized mean lifetimes between 40 – 90 μs, but do not give a clear advantage in terms of efficiency for higher mean lifetime mc-Si material because they are often limited by recombination in the phosphorus diffused emitter region. Heteroemitter designs instead increase in cell efficiency considerable up to generalized mean lifetimes of 380 μs because they are significantly less limited by recombination in the emitter and the bulk lifetime becomes more important. In conclusion, to benefit from increasing mc-Si lifetime, new cell designs, especially heteroemitter, are desirable.

  13. High efficiency thin film CdTe and a-Si based solar cells

    SciTech Connect (OSTI)

    Compaan, A. D.; Deng, X.; Bohn, R. G.

    2000-01-04

    This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and {approximately}9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence features and studied their correlation with cell performance including their dependence on temperature and E-fields; studied band-tail absorption in CdS{sub x}Te{sub 1{minus}x} films at 10 K and 300 K; collaborated with the National CdTe PV Team on (1) studies of high-resistivity tin oxide (HRT) layers from ITN Energy Systems, (2) fabrication of cells on the HRT layers with 0, 300, and 800-nm CdS, and (3) preparation of ZnTe:N-based contacts on First Solar materials for stress testing; and collaborated with Brooklyn College for ellipsometry studies of CdS{sub x}Te{sub 1{minus}x} alloy films, and with the University of Buffalo/Brookhaven NSLS for synchrotron X-ray fluorescence studies of interdiffusion in CdS/CdTe bilayers. The a-Si group established a baseline for fabricating a-Si-based solar cells with single, tandem, and triple-junction structures; fabricated a-Si/a-SiGe/a-SiGe triple-junction solar cells with an initial efficiency of 9.7% during the second quarter, and 10.6% during the fourth quarter (after 1166 hours of light-soaking under 1-sun light intensity at 50 C, the 10.6% solar cells stabilized at about 9%); fabricated wide-bandgap a-Si top cells, the highest Voc achieved for the single-junction top cell was 1.02 V, and top cells with high FF (up to 74%) were fabricated routinely; fabricated high-quality narrow-bandgap a-SiGe solar cells with 8.3% efficiency; found that bandgap-graded buffer layers improve the performance (Voc and FF) of the narrow-bandgap a-SiGe bottom cells; and found that a small amount of oxygen partial pressure ({approximately}2 {times} 10

  14. Solion ion source for high-efficiency, high-throughput solar cell manufacturing

    SciTech Connect (OSTI)

    Koo, John Binns, Brant; Miller, Timothy; Krause, Stephen; Skinner, Wesley; Mullin, James

    2014-02-15

    In this paper, we introduce the Solion ion source for high-throughput solar cell doping. As the source power is increased to enable higher throughput, negative effects degrade the lifetime of the plasma chamber and the extraction electrodes. In order to improve efficiency, we have explored a wide range of electron energies and determined the conditions which best suit production. To extend the lifetime of the source we have developed an in situ cleaning method using only existing hardware. With these combinations, source life-times of >200 h for phosphorous and >100 h for boron ion beams have been achieved while maintaining 1100 cell-per-hour production.

  15. Controlling the conduction band offset for highly efficient ZnO nanorods based perovskite solar cell

    SciTech Connect (OSTI)

    Dong, Juan; Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2015-08-17

    The mechanism of charge recombination at the interface of n-type electron transport layer (n-ETL) and perovskite absorber on the carrier properties in the perovskite solar cell is theoretically studied. By solving the one dimensional diffusion equation with different boundary conditions, it reveals that the interface charge recombination in the perovskite solar cell can be suppressed by adjusting the conduction band offset (ΔE{sub C}) at ZnO ETL/perovskite absorber interface, thus leading to improvements in cell performance. Furthermore, Mg doped ZnO nanorods ETL has been designed to control the energy band levels. By optimizing the doping amount of Mg, the conduction band minimum of the Mg doped ZnO ETL has been raised up by 0.29 eV and a positive ΔE{sub C} of about 0.1 eV is obtained. The photovoltage of the cell is thus significantly increased due to the relatively low charge recombination.

  16. High Efficiency Solar-based Catalytic Structure for CO{sub 2} Reforming

    SciTech Connect (OSTI)

    Menkara, Hisham

    2013-09-30

    Throughout this project, we developed and optimized various photocatalyst structures for CO{sub 2} reforming into hydrocarbon fuels and various commodity chemical products. We also built several closed-loop and continuous fixed-bed photocatalytic reactor system prototypes for a larger-scale demonstration of CO{sub 2} reforming into hydrocarbons, mainly methane and formic acid. The results achieved have indicated that with each type of reactor and structure, high reforming yields can be obtained by refining the structural and operational conditions of the reactor, as well as by using various sacrificial agents (hole scavengers). We have also demonstrated, for the first time, that an aqueous solution containing acid whey (a common bio waste) is a highly effective hole scavenger for a solar-based photocatalytic reactor system and can help reform CO{sub 2} into several products at once. The optimization tasks performed throughout the project have resulted in efficiency increase in our conventional reactors from an initial 0.02% to about 0.25%, which is 10X higher than our original project goal. When acid whey was used as a sacrificial agent, the achieved energy efficiency for formic acid alone was ~0.4%, which is 16X that of our original project goal and higher than anything ever reported for a solar-based photocatalytic reactor. Therefore, by carefully selecting sacrificial agents, it should be possible to reach energy efficiency in the range of the photosynthetic efficiency of typical crop and biofuel plants (1-3%).

  17. High efficiency solar cells combining a perovskite and a silicon heterojunction solar cells via an optical splitting system

    SciTech Connect (OSTI)

    Uzu, Hisashi E-mail: npark@skku.edu; Ichikawa, Mitsuru; Hino, Masashi; Nakano, Kunihiro; Meguro, Tomomi; Yamamoto, Kenji; Hernández, José Luis; Kim, Hui-Seon; Park, Nam-Gyu E-mail: npark@skku.edu

    2015-01-05

    We have applied an optical splitting system in order to achieve very high conversion efficiency for a full spectrum multi-junction solar cell. This system consists of multiple solar cells with different band gap optically coupled via an “optical splitter.” An optical splitter is a multi-layered beam splitter with very high reflection in the shorter-wave-length range and very high transmission in the longer-wave-length range. By splitting the incident solar spectrum and distributing it to each solar cell, the solar energy can be managed more efficiently. We have fabricated optical splitters and used them with a wide-gap amorphous silicon (a-Si) solar cell or a CH{sub 3}NH{sub 3}PbI{sub 3} perovskite solar cell as top cells, combined with mono-crystalline silicon heterojunction (HJ) solar cells as bottom cells. We have achieved with a 550 nm cutoff splitter an active area conversion efficiency of over 25% using a-Si and HJ solar cells and 28% using perovskite and HJ solar cells.

  18. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology

    SciTech Connect (OSTI)

    Vernon, S.M. )

    1993-04-01

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, [approximately] 1 [times] 10[sup 5] cm[sup [minus]5], as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 [times]10[sup 7] cm[sup [minus]2]. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  19. Final Report: Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    SciTech Connect (OSTI)

    Bedair, Salah M.; Hauser, John R.; Elmasry, Nadia; Colter, Peter C.; Bradshaw, G.; Carlin, C. Z.; Samberg, J.; Edmonson, Kenneth

    2012-07-31

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  20. Highly efficient dye-sensitized solar cell with GNS/MWCNT/PANI as a counter electrode

    SciTech Connect (OSTI)

    Al-bahrani, Majid Raissan; Xu, Xiaobao; Ahmad, Waqar; Ren, Xiaoliang; Su, Jun; Cheng, Ze; Gao, Yihua

    2014-11-15

    Highlights: • High-performance PANI/MWCNT-CE was incorporated in a Pt-CE in DSSCs. • GNS/MWCNT/PANI-CE exhibits a high power conversion efficiency (PCE) of 7.52%. • GNS/MWCNT/PANI composite has a high catalytic activity for the reduction of I{sub 3}{sup −}. • GNS/MWCNT/PANI composite has a low R{sub CT} on the electrolyte/CE interface. - Abstract: A graphene-based nanosheet composite/multiwalled carbon nanotube/polyaniline (GNS/MWCNT/PANI) was synthesized via an in situ polymerization technique and applied by the spin-coating method as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). The combination of the high catalytic activity of PANI and outstanding conductivity of GNS/MWCNT improved the photovoltaic performance of the hybrid CE. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed that the GNS/MWCNT/PANI composite has high catalytic activity for the reduction of triiodide to iodide and low charge-transfer resistance at the electrolyte/electrode interface. Transmission electron microscopy (TEM) images showed that the GNS/MWCNT/PANI-CE has a rough and porous structure and X-ray diffraction analysis confirmed the formation of PANI coating on the surface of the GNS/CNT. In particular, current–voltage measurements showed the superior power conversion efficiency (PCE) of 7.52% of the DSSC based on GNS/MWCNT/PANI-CE compared to the PCE of 6.69% of the DSSC based on Pt-CE.

  1. Evaluation of Lifetime of High Efficiency Organic Photovoltaic Devices: Cooperative Research and Development Final Report, CRADA Number CRD-10-379

    SciTech Connect (OSTI)

    Olson, D.

    2013-04-01

    As a part of this joint work, Solarmer and NREL will investigate the lifetime and stability of Organic Photovoltaic Devices based on Solarmer high efficiency active layer materials.

  2. Technology Development for High-Efficiency Solar Cells and Modules Using Thin (<80 um) Single-Crystal Silicon Wafers Produced by Epitaxy: June 11, 2011 - April 30, 2013

    SciTech Connect (OSTI)

    Ravi, T. S.

    2013-05-01

    Final technical progress report of Crystal Solar subcontract NEU-31-40054-01. The objective of this 18-month program was to demonstrate the viability of high-efficiency thin (less than 80 um) monocrystalline silicon (Si) solar cells and modules with a low-cost epitaxial growth process.

  3. High efficiency organic photovoltaic cells employing hybridized mixed-planar heterojunctions

    DOE Patents [OSTI]

    Xue, Jiangeng; Uchida, Soichi; Rand, Barry P.; Forrest, Stephen

    2015-08-18

    A device is provided, having a first electrode, a second electrode, and a photoactive region disposed between the first electrode and the second electrode. The photoactive region includes a first photoactive organic layer that is a mixture of an organic acceptor material and an organic donor material, wherein the first photoactive organic layer has a thickness not greater than 0.8 characteristic charge transport lengths; a second photoactive organic layer in direct contact with the first organic layer, wherein the second photoactive organic layer is an unmixed layer of the organic acceptor material of the first photoactive organic layer, and the second photoactive organic layer has a thickness not less than about 0.1 optical absorption lengths; and a third photoactive organic layer disposed between the first electrode and the second electrode and in direct contact with the first photoactive organic layer. The third photoactive organic layer is an unmixed layer of the organic donor layer of the first photoactive organic layer and has a thickness not less than about 0.1 optical absorption lengths.

  4. High efficiency organic photovoltaic cells employing hybridized mixed-planar heterojunctions

    DOE Patents [OSTI]

    Xue, Jiangeng; Uchida, Soichi; Rand, Barry P; Forrest, Stephen

    2013-11-19

    A device is provided, having a first electrode, a second electrode, and a photoactive region disposed between the first electrode and the second electrode. The photoactive region includes a first organic layer comprising a mixture of an organic acceptor material and an organic donor material, wherein the first organic layer has a thickness not greater than 0.8 characteristic charge transport lengths, and a second organic layer in direct contact with the first organic layer, wherein: the second organic layer comprises an unmixed layer of the organic acceptor material or the organic donor material of the first organic layer, and the second organic layer has a thickness not less than about 0.1 optical absorption lengths. Preferably, the first organic layer has a thickness not greater than 0.3 characteristic charge transport lengths. Preferably, the second organic layer has a thickness of not less than about 0.2 optical absorption lengths. Embodiments of the invention can be capable of power efficiencies of 2% or greater, and preferably 5% or greater.

  5. Research on high-efficiency, multiple-gap, multijunction, amorphous-silicon-based alloy thin-film solar cells

    SciTech Connect (OSTI)

    Guha, S. )

    1989-06-01

    This report presents results of research on advancing our understanding of amorphous-silicon-based alloys and their use in small-area multijunction solar cells. The principal objectives of the program are to develop a broad scientific base for the chemical, structural, optical, and electronic properties of amorphous-silicon-based alloys; to determine the optimum properties of these alloy materials as they relate to high-efficiency cells; to determine the optimum device configuration for multijunction cells; and to demonstrate proof-of-concept, multijunction, a-Si-alloy-based solar cells with 18% efficiency under standard AM1.5 global insolation conditions and with an area of at least 1 cm{sup 2}. A major focus of the work done during this reporting period was the optimization of a novel, multiple-graded structure that enhances cell efficiency through band-gap profiling. The principles of the operation of devices incorporating such a structure, computer simulations of those, and experimental results for both single- and multijunction cells prepared by using the novel structure are discussed in detail. 14 refs., 35 figs., 7 tabs.

  6. Silicon sheet with molecular beam epitaxy for high efficiency solar cells. Final technical report, March 22, 1982-April 30, 1984

    SciTech Connect (OSTI)

    Not Available

    1984-01-01

    A two-year program has been carried out for the Jet Propulsion Laboratory in which the UCLA silicon MBE facility has been used to attempt to grow silicon solar cells of high efficiency. MBE ofers the potential of growing complex and arbitrary doping profiles with 10 A depth resolution. It is the only technique taht can readily grow built-in front and back surface fields of any desired depth and value in silicon solar cells, or the more complicated profiles needed for a double junction cascade cell, all in silicon, connected in series by a tunnel junction. Although the dopant control required for such structures has been demonstrated in silicon by UCLA, crystal quality at the p-n junctions is still too poor to allow the other advantages to be exploited. Results from other laboratories indicate that this problem will soon be overcome. A computer analysis of the double cascade all in silicon shows that efficiencies can be raised over that of any single silicon cell by 1 or 2%, and that open circuit voltage of almost twice that of a single cell should be possible.

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

    SciTech Connect (OSTI)

    Chang, Y. L. Gong, S. White, R.; Lu, Z. H.; Wang, X.; Wang, S.; Yang, C.

    2014-04-28

    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.

  8. Architectures and criteria for the design of high efficiency organic photovoltaic cells

    DOE Patents [OSTI]

    Rand, Barry; Forrest, Stephen R; Burk, Diana Pendergrast

    2015-03-24

    An organic photovoltaic cell includes an anode and a cathode, and a plurality of organic semiconductor layers between the anode and the cathode. At least one of the anode and the cathode is transparent. Each two adjacent layers of the plurality of organic semiconductor layers are in direct contact. The plurality of organic semiconductor layers includes an intermediate layer consisting essentially of a photoconductive material, and two sets of at least three layers. A first set of at least three layers is between the intermediate layer and the anode. Each layer of the first set consists essentially of a different organic semiconductor material having a higher LUMO and a higher HOMO, relative to the material of an adjacent layer of the plurality of organic semiconductor layers closer to the cathode. A second set of at least three layers is between the intermediate layer and the cathode. Each layer of the second set consists essentially of a different organic semiconductor material having a lower LUMO and a lower HOMO, relative to the material of an adjacent layer of the plurality of organic semiconductor layers closer to the anode.

  9. Melt-cast organic glasses as high-efficiency fast neutron scintillators

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Carlson, Joseph S.; Feng, Patrick L.

    2016-06-24

    In this work we report a new class of organic-based scintillators that combines several of the desirable attributes of existing crystalline, liquid, and plastic organic scintillators. The prepared materials may be isolated in single crystalline form or melt-cast to produce highly transparent glasses that have been shown to provide high light yields of up to 16,000 photons/MeVee, as evaluated against EJ-200 plastic scintillators and solution-grown trans-stilbene crystals. The prepared organic glasses exhibit neutron/gamma pulse-shape discrimination (PSD) and are compatible with wavelength shifters to reduce optical self-absorption effects that are intrinsic to pure materials such as crystalline organics. In conclusion, themore » combination of high scintillation efficiency, PSD capabilities, and facile scale-up via melt-casting distinguishes this new class of amorphous materials from existing alternatives.« less

  10. Architectures and criteria for the design of high efficiency organic photovoltaic cells

    DOE Patents [OSTI]

    Rand, Barry; Forrest, Stephen R; Pendergrast Burk, Diane

    2015-03-31

    A method for fabricating an organic photovoltaic cell includes providing a first electrode; depositing a series of at least seven layers onto the first electrode, each layer consisting essentially of a different organic semiconductor material, the organic semiconductor material of at least an intermediate layer of the sequence being a photoconductive material; and depositing a second electrode onto the sequence of at least seven layers. One of the first electrode and the second electrode is an anode and the other is a cathode. The organic semiconductor materials of the series of at least seven layers are arranged to provide a sequence of decreasing lowest unoccupied molecular orbitals (LUMOs) and a sequence of decreasing highest occupied molecular orbitals (HOMOs) across the series from the anode to the cathode.

  11. Low Thermal Budget, Photonic-Cured Compact TiO2 Layer for High-Efficiency Perovskite Solar Cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Das, Sanjib; Gu, Gong; Joshi, Pooran C; Aytug, Tolga; Rouleau, Christopher; Geohegan, David B; Xiao, Kai

    2016-01-01

    Rapid advances in organometal trihalide perovskite solar cells (PSCs) have positioned them to be one of the leading next generation photovoltaic technologies. However, most of the high-performance PSCs, particularly those using compact TiO2 as electron transport layer, require a high-temperature sintering step, which is not compatible with flexible polymer-based substrates. Considering the materials of interest for PSCs and corresponding device configurations, it is technologically imperative to fabricate high-efficiency cells at low thermal budget so that they can be realized on low-temperature plastic substrates. We report on a new photonic curing technique that produces high-quality crystalline TiO2 films on indium tinmore » oxide-coated glass and flexible polyethylene terephthalate (PET) substrates. The planar PSCs, using photonic-cured TiO2 films, exhibit PCEs as high as 15.0% and 11.2% on glass and flexible PET substrates, respectively, comparable to the device performance of PSCs incorporating furnace annealed TiO2 films.« less

  12. Low thermal budget, photonic-cured compact TiO2 layers for high-efficiency perovskite solar cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Das, Sanjib; Gu, Gong; Joshi, Pooran C.; Yang, Bin; Aytug, Tolga; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai

    2016-05-25

    Rapid advances in organometallic trihalide perovskite solar cells (PSCs) have positioned them to be one of the leading next generation photovoltaic technologies. However, most of the high-performance PSCs, particularly those using compact TiO2 as an electron transport layer, require a high-temperature sintering step, which is not compatible with flexible polymer-based substrates. Considering the materials of interest for PSCs and corresponding device configurations, it is technologically imperative to fabricate high-efficiency cells at low thermal budget so that they can be realized on low-temperature plastic substrates. In this paper, we report on a new photonic curing technique that produces crystalline anatase-phase TiO2more » films on indium tin oxide-coated glass and flexible polyethylene terephthalate (PET) substrates. Finally, the planar PSCs, using photonic-cured TiO2 films, exhibit PCEs as high as 15.0% and 11.2% on glass and flexible PET substrates, respectively, comparable to the device performance of PSCs incorporating furnace annealed TiO2 films.« less

  13. Highly Efficient 32.3% Monolithic GaInP/GaAs/Ge Triple Junction Concentrator Solar Cells

    SciTech Connect (OSTI)

    Cotal, H. L.; Lillington, D. R.; Ermer, J. H.; King, R. R.; Karam, N. H.; Kurtz, S. R.; Friedman, D. J.; Olson, J. M.; Ward, S.; Duda, A.; Emery, K. A.; Moriarty, T.

    2000-01-01

    Based on recent cell improvements for space applications, multijunction cells apear to be ideal candidates for high efficiency, cost effective, PV concentrator systems.

  14. Highly efficient terahertz wave modulators by photo-excitation of organics/silicon bilayers

    SciTech Connect (OSTI)

    Yoo, Hyung Keun; Kang, Chul; Hwang, In-Wook; Yoon, Youngwoon; Lee, Kiejin; Kee, Chul-Sik; Lee, Joong Wook

    2014-07-07

    Using hybrid bilayer systems comprising a molecular organic semiconductor and silicon, we achieve optically controllable active terahertz (THz) modulators that exhibit extremely high modulation efficiencies. A modulation efficiency of 98% is achieved from thermally annealed C{sub 60}/silicon bilayers, due to the rapid photo-induced electron transfer from the excited states of the silicon onto the C{sub 60} layer. Furthermore, we demonstrate the broadband modulation of THz waves. The cut-off condition of the system that is determined by the formation of efficient charge separation by the photo-excitation is highly variable, changing the system from insulating to metallic. The phenomenon enables an extremely high modulation bandwidth and rates of electromagnetic waves of interest. The realization of near-perfect modulation efficiency in THz frequencies opens up the possibilities of utilizing active modulators for THz spectroscopy and communications.

  15. Efficient CO2 Fixation Pathways: Energy Plant: High Efficiency Photosynthetic Organisms

    SciTech Connect (OSTI)

    2012-01-01

    PETRO Project: UCLA is redesigning the carbon fixation pathways of plants to make them more efficient at capturing the energy in sunlight. Carbon fixation is the key process that plants use to convert carbon dioxide (CO2) from the atmosphere into higher energy molecules (such as sugars) using energy from the sun. UCLA is addressing the inefficiency of the process through an alternative biochemical pathway that uses 50% less energy than the pathway used by all land plants. In addition, instead of producing sugars, UCLA’s designer pathway will produce pyruvate, the precursor of choice for a wide variety of liquid fuels. Theoretically, the new biochemical pathway will allow a plant to capture 200% as much CO2 using the same amount of light. The pathways will first be tested on model photosynthetic organisms and later incorporated into other plants, thus dramatically improving the productivity of both food and fuel crops.

  16. Metal Halide Solid-State Surface Treatment for High Efficiency PbS and PbSe QD Solar Cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Crisp, R. W.; Kroupa, D. M.; Marshall, A. R.; Miller, E. M.; Zhang, J.; Beard, M. C.; Luther, J. M.

    2015-04-24

    We developed a layer-by-layer method of preparing PbE (E = S or Se) quantum dot (QD) solar cells using metal halide (PbI2, PbCl2, CdI2, or CdCl2) salts dissolved in dimethylformamide to displace oleate surface ligands and form conductive QD solids. The resulting QD solids have a significant reduction in the carbon content compared to films treated with thiols and organic halides. We find that the PbI2 treatment is the most successful in removing alkyl surface ligands and also replaces most surface bound Cl- with I-. The treatment protocol results in PbS QD films exhibiting a deeper work function and bandmore » positions than other ligand exchanges reported previously. The method developed here produces solar cells that perform well even at film thicknesses approaching a micron, indicating improved carrier transport in the QD films. We demonstrate QD solar cells based on PbI2 with power conversion efficiencies above 7%.« less

  17. Metal Halide Solid-State Surface Treatment for High Efficiency PbS and PbSe QD Solar Cells

    SciTech Connect (OSTI)

    Crisp, R. W.; Kroupa, D. M.; Marshall, A. R.; Miller, E. M.; Zhang, J.; Beard, M. C.; Luther, J. M.

    2015-04-24

    We developed a layer-by-layer method of preparing PbE (E = S or Se) quantum dot (QD) solar cells using metal halide (PbI2, PbCl2, CdI2, or CdCl2) salts dissolved in dimethylformamide to displace oleate surface ligands and form conductive QD solids. The resulting QD solids have a significant reduction in the carbon content compared to films treated with thiols and organic halides. We find that the PbI2 treatment is the most successful in removing alkyl surface ligands and also replaces most surface bound Cl- with I-. The treatment protocol results in PbS QD films exhibiting a deeper work function and band positions than other ligand exchanges reported previously. The method developed here produces solar cells that perform well even at film thicknesses approaching a micron, indicating improved carrier transport in the QD films. We demonstrate QD solar cells based on PbI2 with power conversion efficiencies above 7%.

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

    SciTech Connect (OSTI)

    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)

    2014-02-17

    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.

  19. Development of low-cost technology for the next generation of high efficiency solar cells composed of earth abundant elements

    SciTech Connect (OSTI)

    Agrawal, Rakesh

    2014-09-28

    characterization analysis techniques have been developed to identify significant limitations to traditional electrical characterization of CZTSSe devices, and (5) the developed electrical analysis techniques have been used to identify the role that band gap and electrostatic potential fluctuations have in limiting device performance for this material system. The device modeling and characterization of CZTSSe undertaken with this project have significant implications for the CZTSSe research community, as the identified limitations due to potential fluctuations are expected to be a performance limitation to high-efficiency CZTSSe devices fabricated from all current processing techniques. Additionally, improvements realized through enhanced absorber processing conditions to minimize nanoparticle and large-grain absorber heterogeneity are suggested to be beneficial processing improvements which should be applied to CZTSSe devices fabricated from all processing techniques. Ultimately, our research has indicated that improved performance for CZTSSe will be achieved through novel absorber processing which minimizes defect formation, elemental losses, secondary phase formation, and compositional uniformity in CZTSSe absorbers; we believe this novel absorber processing can be achieved through nanocrystal based processing of CZTSSe which is an active area of research at the conclusion of this award. While significant fundamental understanding of CZTSSe and the performance limitations associated with this material system, as well as notable improvements in the processing of nanocrystal based CZTSSe absorbers, have been achieved under this project, the limitation of two years of research funding towards our goals prevents further significant advancements directly identified through pce. improvements relative to those reported herein. As the characterization and modeling subtask of this project has been the main driving force for understanding device limitations, the conclusions of this

  20. High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells: Final Technical Report, 1 September 2001--6 March 2005

    SciTech Connect (OSTI)

    Deng, X.

    2006-01-01

    The objectives for the University of Toledo are to: (1) establish a transferable knowledge and technology base for fabricating high-efficiency triple-junction a-Si-based solar cells, and (2) develop high-rate deposition techniques for the growing a-Si-based and related alloys, including poly-Si, c-Si, a-SiGe, and a-Si films and photovoltaic devices with these materials.

  1. New concepts for high efficiency energy conversion: The avalanche heterostructure and superlattice solar cells. Subcontract report, 1 June 1987--31 January 1990

    SciTech Connect (OSTI)

    Summers, C.J.; Rohatgi, A.; Torabi, A.; Harris, H.M.

    1993-01-01

    This report describes investigation into the theory and technology of a novel heterojunction or superlattice, single-junction solar cell, which injects electrons across the heterointerface to produce highly efficient impact ionization of carriers in the lowband-gap side of the junction, thereby conserving their total energy. Also, the superlattice structure has the advantage of relaxing the need for perfect lattice matching at the p-n interface and will inhibit the cross diffusion of dopant atoms that typically occurs in heavy doping. This structure avoids the use of tunnel junctions that make it very difficult to achieve the predicted efficiencies in cascade cells, thus making it possible to obtain energy efficiencies that are competitive with those predicted for cascade solar cells with reduced complexity and cost. This cell structure could also be incorporated into other solar cell structures designed for wider spectral coverage.

  2. Final Report- High-Efficiency Low-Cost Solar Receiver for use in a Supercritical CO2 Recompression Cycle

    Office of Energy Efficiency and Renewable Energy (EERE)

    This project has performed solar receiver designs for two supercritical carbon dioxide (sCO2) power cycles. The first half of the program focused on a nominally 2 MWe power cycle, with a receiver designed for test at the Sandia Solar Thermal Test Facility. This led to an economical cavity-type receiver. The second half of the program focused on a 10 MWe power cycle, incorporating a surround open receiver. Rigorous component life and performance testing was performed in support of both receiver designs. The receiver performance objectives are set to conform to the US DOE goals of 6¢/kWh by 2020.

  3. Los Alamos develops new technique for growing high-efficiency...

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

    technique for growing high-efficiency perovskite ... growth of highly efficient and reproducible solar cells from large-area ... clean global energy solutions for the ...

  4. Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations

    SciTech Connect (OSTI)

    Bozzola, A. Kowalczewski, P.; Andreani, L. C.

    2014-03-07

    Thin-film solar cells based on silicon have emerged as an alternative to standard thick wafers technology, but they are less efficient, because of incomplete absorption of sunlight, and non-radiative recombinations. In this paper, we focus on the case of crystalline silicon (c-Si) devices, and we present a full analytic electro-optical model for p-n junction solar cells with Lambertian light trapping. This model is validated against numerical solutions of the drift-diffusion equations. We use this model to investigate the interplay between light trapping, and bulk and surface recombination. Special attention is paid to surface recombination processes, which become more important in thinner devices. These effects are further amplified due to the textures required for light trapping, which lead to increased surface area. We show that c-Si solar cells with thickness of a few microns can overcome 20% efficiency and outperform bulk ones when light trapping is implemented. The optimal device thickness in presence of light trapping, bulk and surface recombination, is quantified to be in the range of 1080??m, depending on the bulk quality. These results hold, provided the effective surface recombination is kept below a critical level of the order of 100?cm/s. We discuss the possibility of meeting this requirement, in the context of state-of-the-art techniques for light trapping and surface passivation. We show that our predictions are within the capability of present day silicon technologies.

  5. High-efficiency, thin-film solar cells. Annual subcontractor report, 1 July 1991--30 June 1992

    SciTech Connect (OSTI)

    Gale, R.P.

    1994-01-01

    This report describes work on a 3-year research program to investigate thin-film GaAs/GaInP cells using the cleavage of lateral epitaxial film for transfer (CLEFT) technique, and to determine the process to enable overgrowth of GaAs films using organometallic chemistry. Application of the CLEFT thin-film technique to GaInP/GaAs solar cells and organometallic overgrowth was investigated. A problem of alloy contamination was identified and controlled, leading to higher quality layers. Solar cell structures were grown and fabricated using previously determined growth parameters for GaAs and GaInP. With the improved materials developed significant improvements were made in solar cell performance. Conditions for in-situ overgrowth by organometallic chemical vapor deposition (OMCVD) were determined and continuous GaAs layers were grown over a separation mask layer. The layers were successfully separated from their substrate using the CLEFT process, demonstrating the application of overgrowth using OM chemistry with HCl.

  6. An easy-to-fabricate low-temperature TiO{sub 2} electron collection layer for high efficiency planar heterojunction perovskite solar cells

    SciTech Connect (OSTI)

    Conings, B.; Baeten, L.; Jacobs, T.; Dera, R.; D’Haen, J.; Manca, J.; Boyen, H.-G.

    2014-08-01

    Organometal trihalide perovskite solar cells arguably represent the most auspicious new photovoltaic technology so far, as they possess an astonishing combination of properties. The impressive and brisk advances achieved so far bring forth highly efficient and solution processable solar cells, holding great promise to grow into a mature technology that is ready to be embedded on a large scale. However, the vast majority of state-of-the-art perovskite solar cells contains a dense TiO{sub 2} electron collection layer that requires a high temperature treatment (>450 °C), which obstructs the road towards roll-to-roll processing on flexible foils that can withstand no more than ∼150 °C. Furthermore, this high temperature treatment leads to an overall increased energy payback time and cumulative energy demand for this emerging photovoltaic technology. Here we present the implementation of an alternative TiO{sub 2} layer formed from an easily prepared nanoparticle dispersion, with annealing needs well within reach of roll-to-roll processing, making this technology also appealing from the energy payback aspect. Chemical and morphological analysis allows to understand and optimize the processing conditions of the TiO{sub 2} layer, finally resulting in a maximum obtained efficiency of 13.6% for a planar heterojunction solar cell within an ITO/TiO{sub 2}/CH{sub 3}NH{sub 3}PbI{sub 3-x}Cl{sub x}poly(3-hexylthiophene)/Ag architecture.

  7. Hydrogenated indium oxide window layers for high-efficiency Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Jäger, Timo Romanyuk, Yaroslav E.; Nishiwaki, Shiro; Bissig, Benjamin; Pianezzi, Fabian; Fuchs, Peter; Gretener, Christina; Tiwari, Ayodhya N.; Döbeli, Max

    2015-05-28

    High mobility hydrogenated indium oxide is investigated as a transparent contact for thin film Cu(In,Ga)Se{sub 2} (CIGS) solar cells. Hydrogen doping of In{sub 2}O{sub 3} thin films is achieved by injection of H{sub 2}O water vapor or H{sub 2} gas during the sputter process. As-deposited amorphous In{sub 2}O{sub 3}:H films exhibit a high electron mobility of ∼50 cm{sup 2}/Vs at room temperature. A bulk hydrogen concentration of ∼4 at. % was measured for both optimized H{sub 2}O and H{sub 2}-processed films, although the H{sub 2}O-derived film exhibits a doping gradient as detected by elastic recoil detection analysis. Amorphous IOH films are implemented as front contacts in CIGS based solar cells, and their performance is compared with the reference ZnO:Al electrodes. The most significant feature of IOH containing devices is an enhanced open circuit voltage (V{sub OC}) of ∼20 mV regardless of the doping approach, whereas the short circuit current and fill factor remain the same for the H{sub 2}O case or slightly decrease for H{sub 2}. The overall power conversion efficiency is improved from 15.7% to 16.2% by substituting ZnO:Al with IOH (H{sub 2}O) as front contacts. Finally, stability tests of non-encapsulated solar cells in dry air at 80 °C and constant illumination for 500 h demonstrate a higher stability for IOH-containing devices.

  8. Module greenhouse with high efficiency of transformation of solar energy, utilizing active and passive glass optical rasters

    SciTech Connect (OSTI)

    Korecko, J.; Jirka, V.; Sourek, B.; Cerveny, J.

    2010-10-15

    Since the eighties of the 20th century, various types of linear glass rasters for architectural usage have been developed in the Czech Republic made by the continuous melting technology. The development was focused on two main groups of rasters - active rasters with linear Fresnel lenses in fixed installation and with movable photo-thermal and/or photo-thermal/photo-voltaic absorbers. The second group are passive rasters based on total reflection of rays on an optical prism. During the last years we have been working on their standardization, exact measuring of their optical and thermal-technical characteristics and on creation of a final product that could be applied in solar architecture. With the project supported by the Ministry of Environment of the Czech Republic we were able to build an experimental greenhouse using these active and passive optical glass rasters. The project followed the growing number of technical objectives. The concept of the greenhouse consisted of interdependence construction - structural design of the greenhouse with its technological equipment securing the required temperature and humidity conditions in the interior of the greenhouse. This article aims to show the merits of the proposed scheme and presents the results of the mathematical model in the TRNSYS environment through which we could predict the future energy balance carried out similar works, thus optimizing the investment and operating costs. In this article description of various technology applications for passive and active utilization of solar radiation is presented, as well as some results of short-term and long-term experiments, including evaluation of 1-year operation of the greenhouse from the energy and interior temperature viewpoints. A comparison of the calculated energy flows in the greenhouse to real measured values, for verification of the installed model is also involved. (author)

  9. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.

    2005-10-01

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  10. High Efficiency Amorphous and Microcrystalline Silicon Based Double-Junction Solar Cells made with Very-High-Frequency Glow Discharge

    SciTech Connect (OSTI)

    Banerjee, Arindam

    2004-10-20

    We have achieved a total-area initial efficiency of 11.47% (active-area efficiency of 12.33%) on a-Si:H/?c-Si:H double-junction structure, where the intrinsic layer bottom cell was made in 50 minutes. On another device in which the bottom cell was made in 30 min, we achieved initial total-area efficiency of 10.58% (active-efficiency of 11.35%). We have shown that the phenomenon of ambient degradation of both ?c-Si:H single-junction and a-Si:H/?c-Si:H double-junction cells can be attributed to impurity diffusion after deposition. Optimization of the plasma parameters led to alleviation of the ambient degradation. Appropriate current matching between the top and bottom component cells has resulted in a stable total-area efficiency of 9.7% (active-area efficiency of 10.42%) on an a-Si:H/?c-Si:H double-junction solar cell in which the deposition time for the ?c-Si:H intrinsic layer deposition was of 30 min.

  11. High-Efficiency CdTe and CIGS Thin-Film Solar Cells: Highlights and Challenges; Preprint

    SciTech Connect (OSTI)

    Noufi, R.; Zweibel, K.

    2006-05-01

    Thin-film photovoltaic (PV) modules of CdTe and Cu(In,Ga)Se2 (CIGS) have the potential to reach cost-effective PV-generated electricity. These technologies have transitioned from the laboratory to the market place. Pilot production and first-time manufacturing are ramping up to higher capacity and enjoying a flood of venture-capital funding. CIGS solar cells and modules have achieved 19.5% and 13% efficiencies, respectively. Likewise, CdTe cells and modules have reached 16.5% and 10.2% efficiencies, respectively. Even higher efficiencies from the laboratory and from the manufacturing line are only a matter of time. Manufacturing-line yield continues to improve and is surpassing 85%. Long-term stability has been demonstrated for both technologies; however, some failures in the field have also been observed, emphasizing the critical need for understanding degradation mechanisms and packaging options. The long-term potential of the two technologies require R&D emphasis on science and engineering-based challenges to find solutions to achieve targeted cost-effective module performance, and in-field durability. Some of the challenges are common to both, e.g., in-situ process control and diagnostics, thinner absorber, understanding degradation mechanisms, protection from water vapor, and innovation in high-speed processing and module design. Other topics are specific to the technology, such as lower-cost and fast-deposition processes for CIGS, and improved back contact and voltage for CdTe devices.

  12. Remnant PbI{sub 2}, an unforeseen necessity in high-efficiency hybrid perovskite-based solar cells?

    SciTech Connect (OSTI)

    Cao, Duyen H.; Stoumpos, Constantinos C.; Malliakas, Christos D.; Katz, Michael J.; Hupp, Joseph T. E-mail: m-kanatzidis@northwestern.edu; Kanatzidis, Mercouri G. E-mail: m-kanatzidis@northwestern.edu; Farha, Omar K.

    2014-09-01

    Perovskite-containing solar cells were fabricated in a two-step procedure in which PbI{sub 2} is deposited via spin-coating and subsequently converted to the CH{sub 3}NH{sub 3}PbI{sub 3} perovskite by dipping in a solution of CH{sub 3}NH{sub 3}I. By varying the dipping time from 5 s to 2 h, we observe that the device performance shows an unexpectedly remarkable trend. At dipping times below 15 min the current density and voltage of the device are enhanced from 10.1 mA/cm{sup 2} and 933 mV (5 s) to 15.1 mA/cm{sup 2} and 1036 mV (15 min). However, upon further conversion, the current density decreases to 9.7 mA/cm{sup 2} and 846 mV after 2 h. Based on X-ray diffraction data, we determined that remnant PbI{sub 2} is always present in these devices. Work function and dark current measurements showed that the remnant PbI{sub 2} has a beneficial effect and acts as a blocking layer between the TiO{sub 2} semiconductor and the perovskite itself reducing the probability of back electron transfer (charge recombination). Furthermore, we find that increased dipping time leads to an increase in the size of perovskite crystals at the perovskite-hole-transporting material interface. Overall, approximately 15 min dipping time (?2% unconverted PbI{sub 2}) is necessary for achieving optimal device efficiency.

  13. Organic Solar Cells: Absolute Measurement of Domain Composition...

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

    Organic Solar Cells: Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in Solar Cells Organic Solar Cells: Absolute Measurement of...

  14. Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network

    SciTech Connect (OSTI)

    Shui, Jianglan; Chen, Chen; Grabstanowicz, Lauren; Zhao, Dan; Liu, Di -Jia

    2015-08-25

    Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A∙cm-3 at 0.9 V or 450 A∙cm-3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed.

  15. Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shui, Jianglan; Chen, Chen; Grabstanowicz, Lauren; Zhao, Dan; Liu, Di -Jia

    2015-08-25

    Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report heremore » a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A∙cm-3 at 0.9 V or 450 A∙cm-3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed.« less

  16. InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

    SciTech Connect (OSTI)

    Alonso-lvarez, D.; Thomas, T.; Fhrer, M.; Hylton, N. P.; Ekins-Daukes, N. J.; Lackner, D.; Philipps, S. P.; Bett, A. W.; Sodabanlu, H.; Fujii, H.; Watanabe, K.; Sugiyama, M.; Nasi, L.; Campanini, M.

    2014-08-25

    Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6 misoriented substrates under the usual growth conditions. The presence of wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1??s, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.

  17. Interface engineering for efficient fullerene-free organic solar cells

    SciTech Connect (OSTI)

    Shivanna, Ravichandran; Narayan, K. S. E-mail: narayan@jncasr.ac.in; Rajaram, Sridhar E-mail: narayan@jncasr.ac.in

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  18. High efficiency diamond solar cells

    DOE Patents [OSTI]

    Gruen, Dieter M.

    2008-05-06

    A photovoltaic device and method of making same. A layer of p-doped microcrystalline diamond is deposited on a layer of n-doped ultrananocrystalline diamond such as by providing a substrate in a chamber, providing a first atmosphere containing about 1% by volume CH.sub.4 and about 99% by volume H.sub.2 with dopant quantities of a boron compound, subjecting the atmosphere to microwave energy to deposit a p-doped microcrystalline diamond layer on the substrate, providing a second atmosphere of about 1% by volume CH.sub.4 and about 89% by volume Ar and about 10% by volume N.sub.2, subjecting the second atmosphere to microwave energy to deposit a n-doped ultrananocrystalline diamond layer on the p-doped microcrystalline diamond layer. Electrodes and leads are added to conduct electrical energy when the layers are irradiated.

  19. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic...

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

    Tidal Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles ... High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters United ...

  20. High-efficiency photovoltaic cells

    DOE Patents [OSTI]

    Yang, H.T.; Zehr, S.W.

    1982-06-21

    High efficiency solar converters comprised of a two cell, non-lattice matched, monolithic stacked semiconductor configuration using optimum pairs of cells having bandgaps in the range 1.6 to 1.7 eV and 0.95 to 1.1 eV, and a method of fabrication thereof, are disclosed. The high band gap subcells are fabricated using metal organic chemical vapor deposition (MOCVD), liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE) to produce the required AlGaAs layers of optimized composition, thickness and doping to produce high performance, heteroface homojunction devices. The low bandgap subcells are similarly fabricated from AlGa(As)Sb compositions by LPE, MBE or MOCVD. These subcells are then coupled to form a monolithic structure by an appropriate bonding technique which also forms the required transparent intercell ohmic contact (IOC) between the two subcells. Improved ohmic contacts to the high bandgap semiconductor structure can be formed by vacuum evaporating to suitable metal or semiconductor materials which react during laser annealing to form a low bandgap semiconductor which provides a low contact resistance structure.

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

    SciTech Connect (OSTI)

    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)

    2014-01-27

    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.

  2. GaInNAs Structures Grown by MBE for High-Efficiency Solar Cells: Final Report; 25 June 1999--24 August 2002

    SciTech Connect (OSTI)

    Tu, C. W.

    2003-08-01

    The focus of this work is to improve the quality of GaInNAs by advanced thin-film growth techniques, such as digital-alloy growth techniques and migration-enhanced epitaxy (MEE). The other focus is to further investigate the properties of such materials, which are potentially beneficial for high-efficiency, multijunction solar cells. 400-nm-thick strain-compensated Ga0.92In0.08As/GaN0.03As0.97 short-period superlattices (SPSLs) are grown lattice-matched to GaAs substrates. The photoluminescence (PL) intensity of digital alloys is 3 times higher than that of random alloys at room temperature, and the improvement is even greater at low temperature, by a factor of about 12. The room-temperature PL intensity of the GaInNAs quantum well grown by the strained InAs/GaN0.023As SPSL growth mode is higher by a factor 5 as compare to the continuous growth mode. The SPSL growth method allows for independent adjustment of the In-to-Ga ratio without group III competition. MEE reduces the low-energy tail of PL, and PL peaks become more intense and sharper. The twin peaks photoluminescence of GaNAs grown on GaAs was observed at room temperature. The peaks splitting increase with increase in nitrogen alloy content. The strain-induced splitting of light-hole and heavy-hole bands of tensile-strained GaNAs is proposed as an explanation of such behavior.

  3. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive...

  4. Understanding Collection-Related Losses in Organic Solar Cells...

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

    Understanding Collection-Related Losses in Organic Solar Cells Home > Research > ANSER Research Highlights > Understanding Collection-Related Losses in Organic Solar Cells...

  5. High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles...

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

    More Documents & Publications High-Efficiency Low-Cost Solar Receiver for Use in a Supercritical CO2 Recompression Cycle - FY13 Q1 High-Efficiency Receivers for...

  6. HIGH EFFICIENCY SYNGAS GENERATION

    SciTech Connect (OSTI)

    Robert J. Copeland; Yevgenia Gershanovich; Brian Windecker

    2005-02-01

    This project investigated an efficient and low cost method of auto-thermally reforming natural gas to hydrogen and carbon monoxide. Reforming is the highest cost step in producing products such as methanol and Fisher Tropsch liquids (i.e., gas to liquids); and reducing the cost of reforming is the key to reducing the cost of these products. Steam reforming is expensive because of the high cost of the high nickel alloy reforming tubes (i.e., indirectly fired reforming tubes). Conventional auto-thermal or Partial Oxidation (POX) reforming minimizes the size and cost of the reformers and provides a near optimum mixture of CO and hydrogen. However POX requires pure oxygen, which consumes power and significantly increases the cost to reforming. Our high efficiency process extracts oxygen from low-pressure air with novel oxygen sorbent and transfers the oxygen to a nickel-catalyzed reformer. The syngas is generated at process pressure (typically 20 to 40 bar) without nitrogen dilution and has a 1CO to 2H{sub 2} ratio that is near optimum for the subsequent production of Fisher-Tropsch liquid to liquids and other chemicals (i.e., Gas to Liquids, GTL). Our high process efficiency comes from the way we transfer the oxygen into the reformer. All of the components of the process, except for the oxygen sorbent, are commonly used in commercial practice. A process based on a longlived, regenerable, oxygen transfer sorbent could substantially reduce the cost of natural gas reforming to syngas. Lower cost syngas (CO + 2H{sub 2}) that is the feedstock for GTL would reduce the cost of GTL and for other commercial applications (e.g., methanol, other organic chemicals). The vast gas resources of Alaska's North Slope (ANS) offer more than 22 Tcf of gas and GTL production in this application alone, and could account for as much as 300,000 to 700,000 bpd for 20 to 30+ years. We developed a new sorbent, which is an essential part of the High Efficiency Oxygen Process (HOP). We tested the

  7. Recent progress in degradation and stabilization of organic solar cells

    SciTech Connect (OSTI)

    Cao, Huanqi; He, Weidong; Mao, Yiwu; Lin, Xiao; Ishikawa, Ken; Dickerson, James H.; Hess, Wayne P.

    2014-10-15

    Stability is of paramount importance in organic semiconductor devices, especially in organic solar cells (OSCs). Serious degradation in air limits wide applications of these flexible, light-weight and low-cost power-generation devices. Studying the stability of organic solar cells will help us understand degradation mechanisms and further improve the stability of these devices. There are many investigations into the efficiency and stability of OSCs. The efficiency and stability of devices even of the same photoactive materials are scattered in different papers. In particular, the extrinsic degradation that mainly occurs near the interface between the organic layer and the cathode is a major stability concern. In the past few years, researchers have developed many new cathodes and cathode buffer layers, some of which have astonishingly improved the stability of OSCs. In this review article, we discuss the recent developments of these materials and summarize recent progresses in the study of the degradation/stability of OSCs, with emphasis on the extrinsic degradation/stability that is related to the intrusion of oxygen and water. The review provides detailed insight into the current status of research on the stability of OSCs and seeks to facilitate the development of highly-efficient OSCs with enhanced stability.

  8. High-Efficiency Amorphous Silicon and Nanocrystalline Silicon Based Solar Cells and Modules: Annual Technical Progress Report, 30 January 2006 - 29 January 29, 2007

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.

    2007-07-01

    United Solar used a-Si:H/a-SiGe:H/a-SiGe:H in two manufacturing plants and improved solar efficiency and reduced manufacturing cost by new deposition methods, optimized deposition parameters, and new materials and cell structures.

  9. High efficiency incandescent lighting

    DOE Patents [OSTI]

    Bermel, Peter; Ilic, Ognjen; Chan, Walker R.; Musabeyoglu, Ahmet; Cukierman, Aviv Ruben; Harradon, Michael Robert; Celanovic, Ivan; Soljacic, Marin

    2014-09-02

    Incandescent lighting structure. The structure includes a thermal emitter that can, but does not have to, include a first photonic crystal on its surface to tailor thermal emission coupled to, in a high-view-factor geometry, a second photonic filter selected to reflect infrared radiation back to the emitter while passing visible light. This structure is highly efficient as compared to standard incandescent light bulbs.

  10. Organic Solar Cells: Absolute Measurement of Domain Composition and

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

    Nanoscale Size Distribution Explains Performance in Solar Cells Organic Solar Cells: Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in Solar Cells Organic Solar Cells: Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in Solar Cells Print Tuesday, 22 January 2013 00:00 This front cover represents the morphology and resulting device dynamics in organic solar cell blend films of PTB7 and PC71BM, as

  11. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    Improving Solar Cell Models Organic photovoltaics (OPVs), or solar cells, have the potential to provide a low-cost and renewable source of environmentally friendly energy. ...

  12. High efficiency photoionization detector

    DOE Patents [OSTI]

    Anderson, David F.

    1984-01-01

    A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36.+-.0.02 eV, and a vapor pressure of 0.35 torr at 20.degree. C.

  13. High efficiency photoionization detector

    DOE Patents [OSTI]

    Anderson, D.F.

    1984-01-31

    A high efficiency photoionization detector is described using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 [+-] 0.02 eV, and a vapor pressure of 0.35 torr at 20 C. 6 figs.

  14. Project Profile: Development and Productization of High-Efficiency, Low-Cost Building-Integrated PV Shingles Using Monocrystalline Silicon Thin-Film Solar Cells

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Solexel-OC team is developing a BIPV roofing shingle product that includes low-profile solar modules and a unique attachment system that will be fastened directly to the roof and incorporates...

  15. Understanding Collection-Related Losses in Organic Solar Cells | ANSER

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

    Center | Argonne-Northwestern National Laboratory Understanding Collection-Related Losses in Organic Solar Cells Home > Research > ANSER Research Highlights > Understanding Collection-Related Losses in Organic Solar Cells

  16. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells New Morphological Paradigm Uncovered in Organic Solar Cells Print Wednesday, 27 April 2011 00:00 Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models

  17. Low Cost High Efficiency InP-Based Solar Cells: Cooperative Research and Development Final Report, CRADA Number CRD-09-344

    SciTech Connect (OSTI)

    Wanlass, M.

    2012-07-01

    NREL will develop a method of growing and fabricating single junction InP solar cells on 2-inch InP substrates on which a release layer has been deposited by MicroLink Devices. NREL will transfer to MicroLink the details of the InP solar cell layer structure and test results in order that the 2-inch results can be replicated on 4-inch InP substrates. NREL will develop a method of growing and fabricating single junction InP solar cells, including a metamorphic layer, on 2-inch GaAs substrates on which a release layer has been deposited by MicroLink Devices. NREL will transfer to MicroLink the details of the InP solar cell layer structure and test results in order that the 2-inch results can be replicated on 6-inch GaAs substrates. NREL will perform characterization measurements of the solar cells, including I-V and quantum efficiency measurements at AM1.5 1-sun.

  18. High Efficiency, Clean Combustion

    SciTech Connect (OSTI)

    Donald Stanton

    2010-03-31

    Energy use in trucks has been increasing at a faster rate than that of automobiles within the U.S. transportation sector. According to the Energy Information Administration (EIA) Annual Energy Outlook (AEO), a 23% increase in fuel consumption for the U.S. heavy duty truck segment is expected between 2009 to 2020. The heavy duty vehicle oil consumption is projected to grow between 2009 and 2050 while light duty vehicle (LDV) fuel consumption will eventually experience a decrease. By 2050, the oil consumption rate by LDVs is anticipated to decrease below 2009 levels due to CAFE standards and biofuel use. In contrast, the heavy duty oil consumption rate is anticipated to double. The increasing trend in oil consumption for heavy trucks is linked to the vitality, security, and growth of the U.S. economy. An essential part of a stable and vibrant U.S. economy is a productive U.S. trucking industry. Studies have shown that the U.S. gross domestic product (GDP) is strongly correlated to freight transport. Over 90% of all U.S. freight tonnage is transported by diesel power and over 75% is transported by trucks. Given the vital role that the trucking industry plays in the economy, improving the efficiency of the transportation of goods was a central focus of the Cummins High Efficient Clean Combustion (HECC) program. In a commercial vehicle, the diesel engine remains the largest source of fuel efficiency loss, but remains the greatest opportunity for fuel efficiency improvements. In addition to reducing oil consumption and the dependency on foreign oil, this project will mitigate the impact on the environment by meeting US EPA 2010 emissions regulations. Innovation is a key element in sustaining a U.S. trucking industry that is competitive in global markets. Unlike passenger vehicles, the trucking industry cannot simply downsize the vehicle and still transport the freight with improved efficiency. The truck manufacturing and supporting industries are faced with numerous

  19. Advantage of suppressed non-Langevin recombination in low mobility organic solar cells

    SciTech Connect (OSTI)

    Stolterfoht, Martin; Armin, Ardalan; Pandey, Ajay K.; Burn, Paul L.; Meredith, Paul; Pivrikas, Almantas; Philippa, Bronson; White, Ronald D.

    2014-07-07

    Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC{sub 71}BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersive transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.

  20. High-Efficiency Amorphous Silicon and Nanocrystalline Silicon-Based Solar Cells and Modules: Final Technical Progress Report, 30 January 2006 - 29 January 2008

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.

    2008-05-01

    United Solar Ovonic successfully used its spectrum-splitting a-Si:H/a-SiGe:H/a-SiGe:H triple-junction structure in their manufacturing plants, achieving a manufacturing capacity of 118 MW in 2007, and set up a very aggressive expansion plan to achieve grid parity.

  1. Facile method for synthesis of TiO{sub 2} film and its application in high efficiency dye sensitized-solar cell (DSSC)

    SciTech Connect (OSTI)

    Widiyandari, Hendri Gunawan, S. K.V.; Suseno, Jatmiko Endro; Purwanto, Agus; Diharjo, Kuncoro

    2014-02-24

    Dye-sensitized solar cells (DSSC) is a device which converts a solar energy to electrical energy. Different with semiconductor thin film based solar cell, DSSC utilize the sensitized-dye to absorb the photon and semiconductor such as titanium dioxide (TiO{sub 2}) and zinc oxide (ZnO) as a working electrode photoanode. In this report, the preparation of TiO{sub 2} film using a facile method of spray deposition and its application in DSSC have been presented. TiO{sub 2} photoanode was synthesized by growing the droplet of titanium tetraisopropoxide diluted in acid solution on the substrate of conductive glass flourine-doped tin oxide (FTO) with variation of precursor volume. DSSC was assemblied by sandwiching both of photoanode electrode and platinum counter electrode subsequently filling the area between these electrodes with triodine/iodine electrolite solution as redox pairs. The characterization of the as prepared DSSC using solar simulator (AM 1.5G, 100 mW/cm{sup 2}) and I-V source meter Keithley 2400 showed that the performance of DSSC was affected by the precursor volume.. The overall conversion efficiency of DSSC using the optimum TiO{sub 2} film was about 1.97% with the open circuit voltage (V{sub oc}) of 0.73 V, short circuit current density (J{sub sc}) of 4.61 mA and fill factor (FF) of 0.58.

  2. Highly efficient blue organic light emitting device using indium-free transparent anode Ga:ZnO with scalability for large area coating

    SciTech Connect (OSTI)

    Wang, Liang; Matson, Dean W.; Polikarpov, Evgueni; Swensen, James S.; Bonham, Charles C.; Cosimbescu, Lelia; Berry, J. J.; Ginley, D. S.; Gaspar, Daniel J.; Padmaperuma, Asanga B.

    2010-02-15

    The availability of economically-produced and environmentally-stable transparent conductive oxide (TCO) coatings is critical for the development of a variety of electronic devices requiring transparent electrodes. Such devices include liquid crystal display pixels and organic light emitting diodes (OLEDs),[1, 2] solar cell applications,[3, 4] and electrically heated windows.[5, 6] The materials fulfilling these requirements are usually wide band gap inorganic transparent conductive oxides (TCOs). Tin-doped indium oxide, or ITO, has traditionally been used for electronic TCO applications because of its low resistivity, high work function and transparency. Due to the increasing cost and limited supply of indium and its tendency to migrate in to the device, there has been increasing research interest to substitute ITO with an indium-free material. A number of alternative metal oxides and doped oxides have been evaluated as TCO materials with varying degrees of success.[7, 8] Among these alternatives to ITO, gallium-doped zinc oxide (GZO) [2, 9] and aluminium-doped zinc oxide (AZO) [10, 11] have drawn particular attention. These materials have been demonstrated to have resistivities and transparencies approaching those of the best ITO, low toxicity, and much lower materials cost. Although AZO is attractive as a TCO electrode material, GZO features a greater resistance to oxidation as a result of gallium’s greater electronegativity compared to Submitted to 2 aluminum.[12, 13

  3. High-efficiency CARM

    SciTech Connect (OSTI)

    Bratman, V.L.; Kol`chugin, B.D.; Samsonov, S.V.; Volkov, A.B.

    1995-12-31

    The Cyclotron Autoresonance Maser (CARM) is a well-known variety of FEMs. Unlike the ubitron in which electrons move in a periodical undulator field, in the CARM the particles move along helical trajectories in a uniform magnetic field. Since it is much simpler to generate strong homogeneous magnetic fields than periodical ones for a relatively low electron energy ({Brit_pounds}{le}1-3 MeV) the period of particles` trajectories in the CARM can be sufficiently smaller than in the undulator in which, moreover, the field decreases rapidly in the transverse direction. In spite of this evident advantage, the number of papers on CARM is an order less than on ubitron, which is apparently caused by the low (not more than 10 %) CARM efficiency in experiments. At the same time, ubitrons operating in two rather complicated regimes-trapping and adiabatic deceleration of particles and combined undulator and reversed guiding fields - yielded efficiencies of 34 % and 27 %, respectively. The aim of this work is to demonstrate that high efficiency can be reached even for a simplest version of the CARM. In order to reduce sensitivity to an axial velocity spread of particles, a short interaction length where electrons underwent only 4-5 cyclotron oscillations was used in this work. Like experiments, a narrow anode outlet of a field-emission electron gun cut out the {open_quotes}most rectilinear{close_quotes} near-axis part of the electron beam. Additionally, magnetic field of a small correcting coil compensated spurious electron oscillations pumped by the anode aperture. A kicker in the form of a sloping to the axis frame with current provided a control value of rotary velocity at a small additional velocity spread. A simple cavity consisting of a cylindrical waveguide section restricted by a cut-off waveguide on the cathode side and by a Bragg reflector on the collector side was used as the CARM-oscillator microwave system.

  4. Polycrystalline silicon passivated tunneling contacts for high efficiency

    Office of Scientific and Technical Information (OSTI)

    silicon solar cells (Journal Article) | SciTech Connect Journal Article: Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells Citation Details In-Document Search Title: Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells Authors: Nemeth, Bill ; Young, David L. ; Page, Matthew R. ; LaSalvia, Vincenzo ; Johnston, Steve ; Reedy, Robert ; Stradins, Paul Publication Date: 2016-03-01 OSTI Identifier: 1247961 Report

  5. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992

    SciTech Connect (OSTI)

    Vernon, S.M.

    1993-04-01

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, {approximately} 1 {times} 10{sup 5} cm{sup {minus}5}, as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 {times}10{sup 7} cm{sup {minus}2}. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  6. Enabling High Efficiency Ethanol Engines

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

    High Efficiency Ethanol Engines (VSSP 12) Presented by Robert Wagner Oak Ridge National ... advantage of the unique properties of ethanol and ethanol-gasoline blends.. 3 Managed ...

  7. Fabrication and characterization of Al{sub 2}O{sub 3} /Si composite nanodome structures for high efficiency crystalline Si thin film solar cells

    SciTech Connect (OSTI)

    Zhang, Ruiying; Zhu, Jian; Zhang, Zhen; Wang, Yanyan; Qiu, Bocang; Liu, Xuehua; Zhang, Jinping; Zhang, Yi; Fang, Qi; Ren, Zhong; Bai, Yu

    2015-12-15

    We report on our fabrication and characterization of Al{sub 2}O{sub 3}/Si composite nanodome (CND) structures, which is composed of Si nanodome structures with a conformal cladding Al{sub 2}O{sub 3} layer to evaluate its optical and electrical performance when it is applied to thin film solar cells. It has been observed that by application of Al{sub 2}O{sub 3}thin film coating using atomic layer deposition (ALD) to the Si nanodome structures, both optical and electrical performances are greatly improved. The reflectivity of less than 3% over the wavelength range of from 200 nm to 2000 nm at an incident angle from 0° to 45° is achieved when the Al{sub 2}O{sub 3} film is 90 nm thick. The ultimate efficiency of around 27% is obtained on the CND textured 2 μm-thick Si solar cells, which is compared to the efficiency of around 25.75% and 15% for the 2 μm-thick Si nanodome surface-decorated and planar samples respectively. Electrical characterization was made by using CND-decorated MOS devices to measure device’s leakage current and capacitance dispersion. It is found the electrical performance is sensitive to the thickness of the Al{sub 2}O{sub 3} film, and the performance is remarkably improved when the dielectric layer thickness is 90 nm thick. The leakage current, which is less than 4x10{sup −9} A/cm{sup 2} over voltage range of from -3 V to 3 V, is reduced by several orders of magnitude. C-V measurements also shows as small as 0.3% of variation in the capacitance over the frequency range from 10 kHz to 500 kHz, which is a strong indication of surface states being fully passivated. TEM examination of CND-decorated samples also reveals the occurrence of SiO{sub x} layer formed between the interface of Si and the Al{sub 2}O{sub 3} film, which is thin enough that ensures the presence of field-effect passivation, From our theoretical and experimental study, we believe Al{sub 2}O{sub 3} coated CND structures is a truly viable approach to achieving higher device

  8. High efficiency and high concentration in photovoltaics

    SciTech Connect (OSTI)

    Yamaguchi, Masafumi; Luque, A.

    1999-10-01

    In this paper, the authors present the state-of-the-art of multijunction solar cells and the future prospects of this technology. Their use in terrestrial applications will likely be for concentrators operating at very high concentrations. Some trends are also discussed and the authors present a cost calculation showing that highly efficient cells under very high concentration would be able to produce electricity at costs competitive with electricity generation costs for some utilities.

  9. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    SciTech Connect (OSTI)

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Br, Marcus; Sadewasser, Sascha

    2014-12-21

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for realistic surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In{sub 1-x}Ga{sub x})Se{sub 2} thin films with an average x?=?[Ga]/([In]?+?[Ga])?=?0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH{sub 3}-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is apart from a slight change in surface composition identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  10. Los Alamos develops new technique for growing high-efficiency perovskite

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

    solar cells Growing high-efficiency perovskite solar cells Los Alamos develops new technique for growing high-efficiency perovskite solar cells Researchers reveal a new solution-based hot-casting technique that allows growth of highly efficient and reproducible solar cells from large-area perovskite crystals. January 29, 2015 Scientists Aditya Mohite, left, and Wanyi Nie are perfecting a crystal production technique to improve perovskite crystal production for solar cells at Los Alamos

  11. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  12. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  13. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  14. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  15. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  16. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  17. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    New Morphological Paradigm Uncovered in Organic Solar Cells Print Organic solar cells are made of light, flexible, renewable materials; they require simple and inexpensive processing steps and could produce an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge separation and transport often depend on

  18. Charge Trapping in High Efficiency Alternating Copolymers: Implications in

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

    Organic Photovoltaic Device Efficiency | ANSER Center | Argonne-Northwestern National Laboratory Charge Trapping in High Efficiency Alternating Copolymers: Implications in Organic Photovoltaic Device Efficiency Home > Research > ANSER Research Highlights > Charge Trapping in High Efficiency Alternating Copolymers: Implications in Organic Photovoltaic Device Efficiency

  19. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    layer. This improved understanding will guide the future development and optimization of organic solar cells by reducing laborious trial-and-error development and forcing other...

  20. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum...

  1. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    an economically competitive and environmentally friendly energy source. Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum...

  2. New Morphological Paradigm Uncovered in Organic Solar Cells

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

    Understanding the fundamentals of organic solar cell function is therefore vital to uncovering their maximum potential. Models describing critical device functions such as charge ...

  3. High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles...

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

    2012. progressreportsunshotbraytonfy12q4.pdf More Documents & Publications High-Efficiency Low-Cost Solar Receiver for Use in a Supercritical CO2 Recompression Cycle - FY13 Q1...

  4. High Efficiency Thermal Energy Storage System for CSP | Department of

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

    Energy Thermal Energy Storage System for CSP High Efficiency Thermal Energy Storage System for CSP This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held April 23-25, 2013 near Phoenix, Arizona. csp_review_meeting_042413_singh.pdf (1.63 MB) More Documents & Publications High Efficiency Thermal Energy Storage System for CSP - FY13 Q1 High-Efficiency Thermal Energy Storage System for CSP - FY13 Q3 High-Efficiency Thermal Energy Storage

  5. High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles |

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

    Department of Energy High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles This fact sheet describes a project awarded under the DOE's 2012 SunShot Concentrating Solar Power R&D award program. The team, led by Brayton Energy, aims to develop and demonstrate a low-cost, high-efficiency solar receiver that is compatible with s-CO2 cycles and modern thermal storage subsystems. Supercritical CO2 Brayton-cycle

  6. Special section guest editorial: Hybrid organic-inorganic solar cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nogueira, Ana Flavia; Rumbles, Garry

    2015-04-06

    In this special section of the Journal of Photonics for Energy, there is a focus on some of the science and technology of a range of different hybrid organic-inorganic solar cells. Prior to 1991 there were many significant scientific research reports of hybrid organic-inorganic solar cells; finally, however, it wasn’t until the dye-sensitized solar cell entered the league table of certified research cell efficiencies that this area experienced an explosion of research activity.

  7. Los Alamos develops new technique for growing high-efficiency perovskite

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

    solar cells Los Alamos develops new technique for growing high-efficiency perovskite solar cells Alumni Link: Opportunities, News and Resources for Former Employees Latest Issue:September 2015 all issues All Issues » submit Los Alamos develops new technique for growing high-efficiency perovskite solar cells Researchers reveal a new solution-based hot-casting technique that allows growth of highly efficient and reproducible solar cells from large-area perovskite crystals. March 1, 2015

  8. High-Efficiency Solar Cogeneration with Thermophotovoltaic &...

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

    predicted to 30% by the end of the decade with decelerating and limited gains thereafter. This technology eliminates electricity consumption during daylight hours, and can increase ...

  9. Structure of All-Polymer Solar Cells Impedes Efficiency

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

    Structure of All-Polymer Solar Cells Impedes Efficiency Print Organic solar cells are made of thin ... networks with sharp interfaces in order to produce high-efficiency devices. ...

  10. Understanding how processing additives tune nanoscale morphology of high efficiency organic photovoltaic blends: From casting solution to spun-cast thin film

    SciTech Connect (OSTI)

    Shao, Ming [ORNL; Keum, Jong Kahk [ORNL; Kumar, Rajeev [ORNL; Chen, Jihua [ORNL; Browning, Jim [ORNL; Chen, Wei [Argonne National Laboratory (ANL); Jianhui, Hou [Chinese Academy of Sciences (CAS), Institute of Chemistry; Do, Changwoo [ORNL; Littrell, Ken [ORNL; Sanjib, Das [University of Tennessee, Knoxville (UTK); Rondinone, Adam Justin [ORNL; Geohegan, David B [ORNL; Sumpter, Bobby G [ORNL; Xiao, Kai [ORNL

    2014-01-01

    Adding a small amount of a processing additive to the casting solution of organic blends has been demonstrated to be an effective method for achieving improved power conversion efficiency (PCE) in organic photovoltaics (OPVs). However, an understanding of the nano-structural evolution occurring in the transformation from casting solution to thin photoactive films is still lacking. In this report, we investigate the effects of the processing additive diiodooctane (DIO) on the morphology of OPV blend of PBDTTT-C-T and fullerene derivative, PC71BM in a casting solution and in spun-cast thin films by using neutron/x-ray scattering, neutron reflectometry and other characterization techniques. The results reveal that DIO has no effect on the solution structures of PBDTTT-C-T and PC71BM. In the spun-cast films, however, DIO is found to promote significantly the molecular ordering of PBDTTT-C-T and PC71BM, and phase segregation, resulting in the improved PCE. Thermodynamic analysis based on Flory-Huggins theory provides a rationale for the effects of DIO on different characteristics of phase segregation as a solvent and due to evaporationg during the film formation. Such information may enable improved rational design of ternary blends to more consistently achieve improved PCE for OPVs.

  11. The influence of molecular orientation on organic bulk heterojunction solar

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

    cells The influence of molecular orientation on organic bulk heterojunction solar cells The influence of molecular orientation on organic bulk heterojunction solar cells Print Monday, 28 April 2014 09:03 Work done on ALS Beamlines 11.0.1.2, 7.3.3, and 5.3.2.2. reveals that preferential orientation of polymer chains with respect to the fullerene domain leads to a high photovoltaic performance. Featured on the cover of Nature Photonics 8. Article link

  12. Special section guest editorial: Hybrid organic-inorganic solar cells

    SciTech Connect (OSTI)

    Nogueira, Ana Flavia; Rumbles, Garry

    2015-04-06

    In this special section of the Journal of Photonics for Energy, there is a focus on some of the science and technology of a range of different hybrid organic-inorganic solar cells. Prior to 1991 there were many significant scientific research reports of hybrid organic-inorganic solar cells; finally, however, it wasn’t until the dye-sensitized solar cell entered the league table of certified research cell efficiencies that this area experienced an explosion of research activity.

  13. High Efficiency Room Air Conditioner

    SciTech Connect (OSTI)

    Bansal, Pradeep

    2015-01-01

    This project was undertaken as a CRADA project between UT-Battelle and Geberal Electric Company and was funded by Department of Energy to design and develop of a high efficiency room air conditioner. A number of novel elements were investigated to improve the energy efficiency of a state-of-the-art WAC with base capacity of 10,000 BTU/h. One of the major modifications was made by downgrading its capacity from 10,000 BTU/hr to 8,000 BTU/hr by replacing the original compressor with a lower capacity (8,000 BTU/hr) but high efficiency compressor having an EER of 9.7 as compared with 9.3 of the original compressor. However, all heat exchangers from the original unit were retained to provide higher EER. The other subsequent major modifications included- (i) the AC fan motor was replaced by a brushless high efficiency ECM motor along with its fan housing, (ii) the capillary tube was replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and (iii) the unit was tested with a drop-in environmentally friendly binary mixture of R32 (90% molar concentration)/R125 (10% molar concentration). The WAC was tested in the environmental chambers at ORNL as per the design rating conditions of AHAM/ASHRAE (Outdoor- 95F and 40%RH, Indoor- 80F, 51.5%RH). All these modifications resulted in enhancing the EER of the WAC by up to 25%.

  14. Adhesion in flexible organic and hybrid organic/inorganic light emitting device and solar cells

    SciTech Connect (OSTI)

    Yu, D.; Kwabi, D.; Akogwu, O.; Du, J.; Oyewole, O. K.; Tong, T.; Anye, V. C.; Rwenyagila, E.; Asare, J.; Fashina, A.; Soboyejo, W. O.

    2014-08-21

    This paper presents the results of an experimental study of the adhesion between bi-material pairs that are relevant to organic light emitting devices, hybrid organic/inorganic light emitting devices, organic bulk heterojunction solar cells, and hybrid organic/inorganic solar cells on flexible substrates. Adhesion between the possible bi-material pairs is measured using force microscopy (AFM) techniques. These include: interfaces that are relevant to organic light emitting devices, hybrid organic/inorganic light emitting devices, bulk heterojunction solar cells, and hybrid combinations of titanium dioxide (TiO{sub 2}) and poly(3-hexylthiophene). The results of AFM measurements are incorporated into the Derjaguin-Muller-Toporov model for the determination of adhesion energies. The implications of the results are then discussed for the design of robust organic and hybrid organic/inorganic electronic devices.

  15. DOE's Launch of High-Efficiency Thermiekectrics Projects | Department of

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

    Energy Launch of High-Efficiency Thermiekectrics Projects DOE's Launch of High-Efficiency Thermiekectrics Projects 2004 Diesel Engine Emissions Reduction (DEER) Conference Presentation: U.S. Department of Energy, EERE 2004_deer_fairbanks2.pdf (1.53 MB) More Documents & Publications Inorganic-Organic Hybrid Thermoelectrics Inorganic-Organic Hybrid Thermoelectrics The 60% Efficient Diesel Engine: Probably, Possible, Or Just a Fantasy?

  16. High Efficiency Engine Technologies Program

    SciTech Connect (OSTI)

    Rich Kruiswyk

    2010-07-13

    Caterpillar's Product Development and Global Technology Division carried out a research program on waste heat recovery with support from DOE (Department of Energy) and the DOE National Energy Technology Laboratory. The objective of the program was to develop a new air management and exhaust energy recovery system that would demonstrate a minimum 10% improvement in thermal efficiency over a base heavy-duty on-highway diesel truck engine. The base engine for this program was a 2007 C15 15.2L series-turbocharged on-highway truck engine with a LPL (low-pressure loop) exhaust recirculation system. The focus of the program was on the development of high efficiency turbomachinery and a high efficiency turbocompound waste heat recovery system. The focus of each area of development was as follows: (1) For turbine stages, the focus was on investigation and development of technologies that would improve on-engine exhaust energy utilization compared to the conventional radial turbines in widespread use today. (2) For compressor stages, the focus was on investigating compressor wheel design parameters beyond the range typically utilized in production, to determine the potential efficiency benefits thereof. (3) For turbocompound, the focus was on the development of a robust bearing system that would provide higher bearing efficiencies compared to systems used in turbocompound power turbines in production. None of the turbocharger technologies investigated involved addition of moving parts, actuators, or exotic materials, thereby increasing the likelihood of a favorable cost-value tradeoff for each technology. And the turbocompound system requires less hardware addition than competing bottoming cycle technologies, making it a more attractive solution from a cost and packaging standpoint. Main outcomes of the program are as follows: (1) Two turbine technologies that demonstrated up to 6% improvement in turbine efficiency on gas stand and 1-3% improvement in thermal efficiency in

  17. Air stable organic-inorganic nanoparticles hybrid solar cells

    DOE Patents [OSTI]

    Qian, Lei; Yang, Jihua; Xue, Jiangeng; Holloway, Paul H.

    2015-09-29

    A solar cell includes a low work function cathode, an active layer of an organic-inorganic nanoparticle composite, a ZnO nanoparticle layer situated between and physically contacting the cathode and active layers; and a transparent high work function anode that is a bilayer electrode. The inclusion of the ZnO nanoparticle layer results in a solar cell displaying a conversion efficiency increase and reduces the device degradation rate. Embodiments of the invention are directed to novel ZnO nanoparticles that are advantageous for use as the ZnO nanoparticle layers of the novel solar cells and a method to prepare the ZnO nanoparticles.

  18. High efficiency laser spectrum conditioner

    DOE Patents [OSTI]

    Greiner, Norman R.

    1980-01-01

    A high efficiency laser spectrum conditioner for generating a collinear parallel output beam containing a predetermined set of frequencies from a multifrequency laser. A diffraction grating and spherical mirror are used in combination, to disperse the various frequencies of the input laser beam and direct these frequencies along various parallel lines spatially separated from one another to an apertured mask. Selection of the desired frequencies is accomplished by placement of apertures at locations on the mask where the desired frequencies intersect the mask. A recollimated parallel output beam with the desired set of frequencies is subsequently generated utilizing a mirror and grating matched and geometrically aligned in the same manner as the input grating and mirror.

  19. Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells

    DOE Patents [OSTI]

    Bhattacharya, Raghu N.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L.; Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

    1998-03-24

    High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

  20. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy

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

    converters - Energy Innovation Portal High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary Matching a semiconductor's bandgap to incident photon energy is a well-known method to achieve the most efficient photovoltaic devices. Since solar radiation consists of a wide range of wavelengths, having one semiconductor with a single bandgap to absorb all solar radiation

  1. Project Profile: High-Efficiency Receivers for Supercritical Carbon Dioxide

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

    Cycles | Department of Energy Receivers for Supercritical Carbon Dioxide Cycles Project Profile: High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles Brayton logo --This project is inactive -- Brayton Energy, under the 2012 SunShot Concentrating Solar Power (CSP) R&D FOA, is building and testing a new solar receiver that uses supercritical carbon dioxide (s-CO2) as the heat-transfer fluid. The research team is designing the receiver to withstand higher operating temperatures

  2. Biomimetic Dye Molecules for Solar Cells

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

    The most cost-effective solar cells are not high-end, high-efficiency single-crystal devices, but rather low-end cells based on organic molecules or conducting polymers. Vital ...

  3. Advanced processing technology for high-efficiency, thin-film CuInSe{sub 2} and CdTe solar cells. Annual subcontract report, 1 March 1993--28 February 1994

    SciTech Connect (OSTI)

    Morel, D.L.; Ferekides, C.S.

    1994-07-01

    This annual report details activities in research on advanced processing technology for high-effiency, thin-film solar cells.

  4. Recyclable organic solar cells on substrates comprising cellulose nanocrystals (CNC)

    SciTech Connect (OSTI)

    Kippelen, Bernard; Fuentes-Hernandez, Canek; Zhou, Yinhua; Moon, Robert; Youngblood, Jeffrey P

    2015-12-01

    Recyclable organic solar cells are disclosed herein. Systems and methods are further disclosed for producing, improving performance, and for recycling the solar cells. In certain example embodiments, the recyclable organic solar cells disclosed herein include: a first electrode; a second electrode; a photoactive layer disposed between the first electrode and the second electrode; an interlayer comprising a Lewis basic oligomer or polymer disposed between the photoactive layer and at least a portion of the first electrode or the second electrode; and a substrate disposed adjacent to the first electrode or the second electrode. The interlayer reduces the work function associated with the first or second electrode. In certain example embodiments, the substrate comprises cellulose nanocrystals that can be recycled. In certain example embodiments, one or more of the first electrode, the photoactive layer, and the second electrode may be applied by a film transfer lamination method.

  5. Nanostructured Thermoelectric Materials and High Efficiency Power...

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

    Nanostructured Thermoelectric Materials and High Efficiency Power Generation Modules Home ... electrical conductivity and thermopower and, simultaneously, low thermal conductivity. ...

  6. High efficiency shale oil recovery

    SciTech Connect (OSTI)

    Adams, D.C.

    1992-01-01

    The overall project objective is to demonstrate the high efficiency of the Adams Counter-Current shale oil recovery process. The efficiency will first be demonstrated on a small scale, in the current phase, after which the demonstration will be extended to the operation of a small pilot plant. Thus the immediate project objective is to obtain data on oil shale retorting operations in a small batch rotary kiln that will be representative of operations in the proposed continuous process pilot plant. Although an oil shale batch sample is sealed in the batch kiln from the start until the end of the run, the process conditions for the batch are the same as the conditions that an element of oil shale would encounter in a continuous process kiln. Similar chemical and physical (heating, mixing) conditions exist in both systems. The two most important data objectives in this phase of the project are to demonstrate (1) that the heat recovery projected for this project is reasonable and (2) that an oil shale kiln will run well and not plug up due to sticking and agglomeration. The following was completed and is reported on this quarter: (1) A software routine was written to eliminate intermittently inaccurate temperature readings. (2) We completed the quartz sand calibration runs, resolving calibration questions from the 3rd quarter. (3) We also made low temperature retorting runs to identify the need for certain kiln modifications and kiln modifications were completed. (4) Heat Conductance data on two Pyrolysis runs were completed on two samples of Occidental oil shale.

  7. Photo electrochemical and organic-based solar cells

    SciTech Connect (OSTI)

    Lewis, N.S.; Kamat, P.; Spitler, M.

    1996-09-01

    Research in solar photoconversion has resulted in significant advances in the fields of photoelectrochemistry and dye-sensitized solar cells. Progress is also evident in the understanding of solid state organic systems for energy transduction. It is evident, however, that the examination in this report of the accomplishments in these areas serves to highlight the great extent of research that is necessary to establish a technology base sufficient for practical application. Recommendations are made in this report on the directions that this research should take.

  8. Scientists at ALS Find New Path to More Efficient Organic Solar...

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

    Scientists at ALS Find New Path to More Efficient Organic Solar Cells Scientists at ALS Find New Path to More Efficient Organic Solar Cells Print Monday, 07 January 2013 00:00 ...

  9. Basic studies of 3-5 high efficiency cell components

    SciTech Connect (OSTI)

    Lundstrom, M.S.; Melloch, M.R.; Pierret, R.F.; Carpenter, M.S.; Chuang, H.L.; Dodd, P.E.; Keshavarzi, A.; Klausmeier-Brown, M.E.; Lush, G.B.; Stellwag, T.B. )

    1993-01-01

    This project's objective is to improve our understanding of the generation, recombination, and transport of carriers within III-V homo- and heterostructures. The research itself consists of fabricating and characterizing solar cell building blocks'' such as junctions and heterojunctions as well as basic measurements of material parameters. A significant effort is also being directed at characterizing loss mechanisms in high-quality, III-V solar cells fabricated in industrial research laboratories throughout the United States. The project's goal is to use our understanding of the device physics of high-efficiency cell components to maximize cell efficiency. A related goal is the demonstration of new cell structures fabricated by molecular beam epitaxy (MBE). The development of measurement techniques and characterization methodologies is also a project objective. This report describes our progress during the fifth and final year of the project. During the past five years, we've teamed a great deal about heavy doping effects in p[sup +] and n[sup +] GaAs and have explored their implications for solar cells. We have developed an understanding of the dominant recombination losses in present-day, high-efficiency cells. We've learned to appreciated the importance of recombination at the perimeter of the cell and have developed techniques for chemically passivating such edges. Finally, we've demonstrated that films grown by molecular beam epitaxy are suitable for high-efficiency cell research.

  10. Enabling High Efficiency Ethanol Engines

    SciTech Connect (OSTI)

    Szybist, J.; Confer, K.

    2011-03-01

    Delphi Automotive Systems and ORNL established this CRADA to explore the potential to improve the energy efficiency of spark-ignited engines operating on ethanol-gasoline blends. By taking advantage of the fuel properties of ethanol, such as high compression ratio and high latent heat of vaporization, it is possible to increase efficiency with ethanol blends. Increasing the efficiency with ethanol-containing blends aims to remove a market barrier of reduced fuel economy with E85 fuel blends, which is currently about 30% lower than with petroleum-derived gasoline. The same or higher engine efficiency is achieved with E85, and the reduction in fuel economy is due to the lower energy density of E85. By making ethanol-blends more efficient, the fuel economy gap between gasoline and E85 can be reduced. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has extensive knowledge and experience in powertrain components and subsystems as well as overcoming real-world implementation barriers. ORNL has extensive knowledge and expertise in non-traditional fuels and improving engine system efficiency for the next generation of internal combustion engines. Partnering to combine these knowledge bases was essential towards making progress to reducing the fuel economy gap between gasoline and E85. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, usually on a bi-weekly basis, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided substantial hardware support to the project by providing components for the single-cylinder engine experiments, engineering support for hardware modifications, guidance for operational strategies on engine research, and hardware support by providing a flexible multi-cylinder engine to be used for optimizing engine efficiency with ethanol-containing fuels.

  11. Organizing and Strategizing a Local/Regional Solar Effort | Department of

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

    Energy Organizing and Strategizing a Local/Regional Solar Effort Organizing and Strategizing a Local/Regional Solar Effort This webinar, "Organizing and Strategizing A Local/Regional Solar Effort," was originally presented on June 14, 2013 as part of the DOE SunShot Initiative's Solar Action Webinar Series. This includes presentations by a number of the program's grant partners, including three cities and one corporate partner, to provide participants' perspectives and present

  12. Promising Technology: High-Efficiency Rooftop Units

    Broader source: Energy.gov [DOE]

    High-efficiency rooftop air conditioning units (RTUs) can significantly reduce heating, cooling, and ventilation energy consumption. High efficiency RTUs incorporate variable speed controls to minimize fan and compressor energy while capturing and reusing heat, cold, and humidity from a building’s exhaust air.

  13. High Efficiency Engine Technologies | Department of Energy

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

    Technologies High Efficiency Engine Technologies The energy wasted in combustion process is a huge untapped resource and the recovery or conversion of this energy into useful power is a huge opportunity. deer09_nelson_2.pdf (285.08 KB) More Documents & Publications Innovative Approaches to Improving Engine Efficiency Overview of High-Efficiency Engine Technologies High Engine Efficiency at 2010 Emissions

  14. Productization and Manufacturing Scaling of High-Efficiency Solar Cell and Module Products Based on a Disruptive Low-Cost, Mono-Crystalline Technology: Final Technical Progress Report, April 1, 2009 - December 30, 2010

    SciTech Connect (OSTI)

    Fatemi, H.

    2012-07-01

    Final report for PV incubator subcontract with Solexel, Inc. The purpose of this project was to develop Solexel's Unique IP, productize it, and transfer it to manufacturing. Silicon constitutes a significant fraction of the total solar cell cost, resulting in an industry-wide drive to lower silicon usage. Solexel's disruptive Solar cell structure got around these challenges and promised superior light trapping, efficiency and mechanical strength, despite being significantly thinner than commercially available cells. Solexel's successful participation in this incubator project became evident as the company is now moving into commercial production and position itself to be competitive for the next Technology Pathway Partnerships (TPP) funding opportunity.

  15. Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices

    SciTech Connect (OSTI)

    Alex Jen; David Ginger; Christine Luscombe; Hong Ma

    2012-04-02

    The aim of our proposal is to apply interface engineering approach to improve charge extraction, guide active layer morphology, improve materials compatibility, and ultimately allow the fabrication of high efficiency tandem cells. Specifically, we aim at developing: i. Interfacial engineering using small molecule self-assembled monolayers ii. Nanostructure engineering in OPVs using polymer brushes iii. Development of efficient light harvesting and high mobility materials for OPVs iv. Physical characterization of the nanostructured systems using electrostatic force microscopy, and conducting atomic force microscopy v. All-solution processed organic-based tandem cells using interfacial engineering to optimize the recombination layer currents vi. Theoretical modeling of charge transport in the active semiconducting layer The material development effort is guided by advanced computer modeling and surface/ interface engineering tools to allow us to obtain better understanding of the effect of electrode modifications on OPV performance for the investigation of more elaborate device structures. The materials and devices developed within this program represent a major conceptual advancement using an integrated approach combining rational molecular design, material, interface, process, and device engineering to achieve solar cells with high efficiency, stability, and the potential to be used for large-area roll-to-roll printing. This may create significant impact in lowering manufacturing cost of polymer solar cells for promoting clean renewable energy use and preventing the side effects from using fossil fuels to impact environment.

  16. Liberty Utilities Iowa High Efficiency Equipment Rebate

    Broader source: Energy.gov [DOE]

    Liberty Utilities offers a rebate to its Iowa residential and small business customers for the purchase of high efficiency ENERGY STAR natural gas home heating and water heating equipment....

  17. Proposal of high efficiency solar cells with closely stacked InAs/In{sub 0.48}Ga{sub 0.52}P quantum dot superlattices: Analysis of polarized absorption characteristics via intermediateband

    SciTech Connect (OSTI)

    Yoshikawa, H. Kotani, T.; Kuzumoto, Y.; Izumi, M.; Tomomura, Y.; Hamaguchi, C.

    2014-07-07

    We present a theoretical study of the electronic structures and polarized absorption properties of quantum dot superlattices (QDSLs) using widegap matrix material, InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs, for realizing intermediateband solar cells (IBSCs) with twostep photonabsorption. The planewave expanded BurtForeman operator ordered 8band kp theory is used for this calculation, where strain effect and piezoelectric effect are taken into account. We find that the absorption spectra of the second transitions of twostep photonabsorption can be shifted to higher energy region by using In{sub 0.48}Ga{sub 0.52}P, which is latticematched material to GaAs substrate, as a matrix material instead of GaAs. We also find that the transverse magnetic polarized absorption spectra in InAs/In{sub 0.48}Ga{sub 0.52}P QDSL with a separate IB from the rest of the conduction minibands can be shifted to higher energy region by decreasing the QD height. As a result, the second transitions of twostep photonabsorption by the sunlight occur efficiently. These results indicate that InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs are suitable material combination of IBSCs toward the realization of ultrahigh efficiency solar cells.

  18. Solar Junction | Open Energy Information

    Open Energy Info (EERE)

    Junction Jump to: navigation, search Name: Solar Junction Place: San Jose, California Zip: CA 95131 Sector: Efficiency, Solar Product: Solar Junction is developing high efficiency...

  19. National Solar Thermal Test Facility

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

    National Solar Thermal Test Facility HomeNational Solar Thermal Test Facility Permalink High-Efficiency Solar Thermochemical Reactor for Hydrogen Production Center for ...

  20. Energetic Barrier Prevents Recombination in Organic Solar Photoconversion Systems (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-08-01

    NREL researchers unravel the factors that affect charge generation and loss in high-performance conjugated polymer-fullerene blends used in organic solar cells.

  1. 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)

    Xiao, Teng

    2012-04-27

    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.

  2. Comment on “Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations” [J. Appl. Phys. 115, 094501 (2014)

    SciTech Connect (OSTI)

    Abenante, L.

    2015-01-14

    In the above paper, an analytical approach including a new solution to the differential diffusion equation in illuminated quasi-neutral regions (QNR) is exploited to calculate the short-circuit current density (J{sub sc}), open-circuit voltage (V{sub oc}), fill factor (FF), and efficiency (η) of light-trapping (LT) c-Si solar cells with a given structure. Comparisons with numerical results calculated by the Silvaco ATLAS device simulator in the same LT cells show that the analytical results are systematically overestimated. According to the authors, the inaccuracies in J{sub sc}, V{sub oc}, and η are due to the fact that assuming ideal collection from space-charge region (SCR) and using the superposition approximation introduce systematic errors into analytical models. In this comment, an analytical approach using reported solutions to the transport equations in QNR and SCR, where ideal collection from SCR is assumed and the superposition approximation is used, is shown to agree with both the Silvaco and PC1d numerical approaches in calculating J{sub sc}, V{sub oc}, and η, in the same LT devices as considered in the commented paper. Reasons for the inaccuracies detected in the commented paper are suggested.

  3. High Efficiency Cold Climate Heat Pump

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

    High Efficiency Cold Climate Heat Pump 2014 Building Technologies Office Peer Review Bo Shen, shenb@ornl.gov Oak Ridge National Laboratory High Efficiency Cold Climate Heat Pump -(CCHP) CRADA Project Summary Timeline: Start date: 01-Oct-2010 Planned end date: 30-Sep-2015 Key Milestones (single-stage) 1. Equipment modeling and EnergyPlus simulation report - March/2013 2. Lab prototype fabricated and installed - Dec/2013 3. Meet 77% capacity at-13°F vs. 47°F; COP=4.1 at 47°F - March/2014

  4. Measure Guideline: High Efficiency Natural Gas Furnaces

    SciTech Connect (OSTI)

    Brand, L.; Rose, W.

    2012-10-01

    This Measure Guideline covers installation of high-efficiency gas furnaces. Topics covered include when to install a high-efficiency gas furnace as a retrofit measure, how to identify and address risks, and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  5. Measure Guideline. High Efficiency Natural Gas Furnaces

    SciTech Connect (OSTI)

    Brand, L.; Rose, W.

    2012-10-01

    This measure guideline covers installation of high-efficiency gas furnaces, including: when to install a high-efficiency gas furnace as a retrofit measure; how to identify and address risks; and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

  6. Recent developments in high-efficiency PV cells

    SciTech Connect (OSTI)

    Deb, S.

    2000-05-22

    Enormous progress has been made in recent years on a number of photovoltaic (PV) materials and devices in terms of conversion efficiencies. Ultrahigh-efficiency (>30{percent}) PV cells have been fabricated from gallium arsenide (GaAs) and its ternary alloys such as gallium indium phosphide (GaInP{sub 2}). The high-efficiency GaAs-based solar cells are being produced on a commercial scale, particularly for space applications. Efficiencies in the range of 18{percent} to 24{percent} have been achieved in traditional silicon-based devices fabricated from both multicrystalline and single-crystal materials. Major advances in efficiency have also been made on various thin-film solar cells based on amorphous silicon (aSi:H), copper gallium indium diselenide (CIGS), and cadmium telluride materials. This paper gives a brief overview of the recent progress in PV cell efficiencies based on these materials and devices.

  7. San Carlos Apache Tribe Energy Organization Analysis & Solar...

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

    ... 1.4MW community-scale solar power @ Apache Gold CasinoResort. * Install solar @ new Bylas ... Energy Summit December 10-11, 2012 Apache Gold CasinoResort San Carlos, Arizona Gail ...

  8. High efficiency novel window air conditioner

    SciTech Connect (OSTI)

    Bansal, Pradeep

    2015-01-01

    This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.

  9. High efficiency novel window air conditioner

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bansal, Pradeep

    2015-01-01

    This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, andmore » R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.« less

  10. High efficiency novel window air conditioner

    SciTech Connect (OSTI)

    Bansal, Pradeep

    2015-07-24

    This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.