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Title: Carrier tunneling and device characteristics in polymer light-emitting diodes

Abstract

This paper demonstrates that the characteristics of light-emitting diodes (LEDs) based upon MEH-PPV, (more fully known as poly(2-methoxy,5-(2{prime}-ethyl-hexoxy)-1,4-phenylene-vinylene)), are determined by tunneling of both the holes and the electrons through interface barriers caused by the band offset between the polymer and the electrodes. It is shown that manipulating these offsets can control the useful operating-voltage of the device as well as its efficiency. A model is developed which clearly explains the device characteristics of a wide range of diodes based upon MEH-PPV. The turn-on voltage for an ideal device is shown to be equal to the band-gap, i.e. 2.1 eV for MEH-PPV, and is slightly lower at 1.8 eV for an indium-tin oxide/MEH-PPV/Ca device. If there is a significant difference in the barrier height, the smaller of the two barriers controls the I-V characteristics while the larger barrier determines the device efficiency. In ITO/MEH-PPV/Ca devices, the barrier to hole injection is 0.2 eV and the barrier to electron injection is only 0.1 eV. The authors show that reducing the hole barrier to 0.1 eV using a polyaniline anode halves the operating voltage and increases device efficiency.

Authors:
 [1]
  1. UNIAX Corp., Santa Barbara, CA (United States)
Publication Date:
OSTI Identifier:
100956
Report Number(s):
CONF-940142-
ISBN 0-8194-1439-5; TRN: IM9540%%430
Resource Type:
Book
Resource Relation:
Conference: OE/LASE `94: conference on optics, electro-optics, and laser applications in science and engineering, Los Angeles, CA (United States), 22-29 Jan 1994; Other Information: PBD: 1994; Related Information: Is Part Of Advanced photonics materials for information technology. Proceedings, SPIE Volume 2144; Etemad, S. [ed.]; PB: 159 p.
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; LIGHT EMITTING DIODES; PERFORMANCE; ELECTROLUMINESCENCE; TUNNEL EFFECT; MATHEMATICAL MODELS; MATERIALS; ELECTRONIC STRUCTURE; EXPERIMENTAL DATA; SEMICONDUCTOR MATERIALS; FIELD EMISSION

Citation Formats

Parker, I D. Carrier tunneling and device characteristics in polymer light-emitting diodes. United States: N. p., 1994. Web.
Parker, I D. Carrier tunneling and device characteristics in polymer light-emitting diodes. United States.
Parker, I D. 1994. "Carrier tunneling and device characteristics in polymer light-emitting diodes". United States.
@article{osti_100956,
title = {Carrier tunneling and device characteristics in polymer light-emitting diodes},
author = {Parker, I D},
abstractNote = {This paper demonstrates that the characteristics of light-emitting diodes (LEDs) based upon MEH-PPV, (more fully known as poly(2-methoxy,5-(2{prime}-ethyl-hexoxy)-1,4-phenylene-vinylene)), are determined by tunneling of both the holes and the electrons through interface barriers caused by the band offset between the polymer and the electrodes. It is shown that manipulating these offsets can control the useful operating-voltage of the device as well as its efficiency. A model is developed which clearly explains the device characteristics of a wide range of diodes based upon MEH-PPV. The turn-on voltage for an ideal device is shown to be equal to the band-gap, i.e. 2.1 eV for MEH-PPV, and is slightly lower at 1.8 eV for an indium-tin oxide/MEH-PPV/Ca device. If there is a significant difference in the barrier height, the smaller of the two barriers controls the I-V characteristics while the larger barrier determines the device efficiency. In ITO/MEH-PPV/Ca devices, the barrier to hole injection is 0.2 eV and the barrier to electron injection is only 0.1 eV. The authors show that reducing the hole barrier to 0.1 eV using a polyaniline anode halves the operating voltage and increases device efficiency.},
doi = {},
url = {https://www.osti.gov/biblio/100956}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Dec 31 00:00:00 EST 1994},
month = {Sat Dec 31 00:00:00 EST 1994}
}

Book:
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