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Nano-Structure Control of Cathode Buffer-Layers and Luminescent Properties of Organic Electroluminescent Device

Published online by Cambridge University Press:  15 March 2011

K. Shinbo
Affiliation:
Dept of Electrical and Electronic Engineering, Niigata Univ, Ikarashi 2-8050, Niigata, Japan
E. Sakai
Affiliation:
Dept of Electrical and Electronic Engineering, Niigata Univ, Ikarashi 2-8050, Niigata, Japan
F. Kaneko
Affiliation:
Dept of Electrical and Electronic Engineering, Niigata Univ, Ikarashi 2-8050, Niigata, Japan
K. Kato
Affiliation:
Dept of Electrical and Electronic Engineering, Niigata Univ, Ikarashi 2-8050, Niigata, Japan
T. Kawakami
Affiliation:
Dept of Electrical and Electronic Engineering, Niigata Univ, Ikarashi 2-8050, Niigata, Japan
T. Tadokoro
Affiliation:
R&D Center, Nippon Seiki Co., Ltd., Hujihashi 1-190-1, Nagaoka 940-2141, Japan
S. Ohta
Affiliation:
R&D Center, Nippon Seiki Co., Ltd., Hujihashi 1-190-1, Nagaoka 940-2141, Japan
R. C. Advincula
Affiliation:
Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294-1240, U.S.A.
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Abstract

Organic light emitting diodes (OLEDs) containing cathode buffer layers of nanometer thickness were fabricated and their electrical and emitting properties were investigated. The OLEDs have an indium tin oxide (ITO) anode/ copper phthalocyanine (CuPc) / N, N'-dephenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) / 8- hydroxyquinoline aluminum (Alq3) / buffer layer / Al cathode structure with the buffer layers made from alternating thin films of Alq3 and Al with nanometer thickness. Improvement of driving voltage and the efficiency for the devices were observed by insertion of the buffer layer. It was estimated that some modulations of the Schottky barrier at the Alq3 and the Al cathode interface were induced due to the insertion of the buffer layer and it caused an enhancement of electron injection from the Al cathode. A model of the band structure at the buffer layer was proposed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

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