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Efficient Polymeric Light-emitting Devices with Aluminum Cathode

Published online by Cambridge University Press:  01 February 2011

X. Y. Deng  and
K. Y. Wong
X. Y. Deng
Affiliation:
Department of Physics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
K. Y. Wong
Affiliation:
Department of Physics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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Abstract

By blending poly(ethylene glycol) (PEG) into an electroluminescence (EL) polymer, significantly enhanced EL efficiency in a polymer light–emitting diode (PLED) with aluminum electrode was achieved. An orange-color-emitting PLED with 10 wt% PEG blending achieved device efficiencies exceeding 2.6 cd/A for a wide range of bias voltage, which is more than two orders of magnitude higher than that for a similar PLED without the PEG blending. A similar enhancement was observed by introducing PEG as an ultra-thin interfacial layer between the emissive polymer and the cathode. The enhancement was also observed for several different species of emissive polymers, and for blending with either PEG or poly(ethylene oxide) (PEO) with different molecular weights. The enhanced efficiency was a result of the reduction of electron injection barrier height at the cathode-polymer interface. It is believed that interfacial interaction that is specific to Al plays an important role in the enhancement mechanism.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 871: Symposium I – Organic Thin-Film Electronics , 2005 , I6.42
Copyright
Copyright © Materials Research Society 2005

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