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Spectroscopic Ellipsometry of the Optical Functions of Some Widely Used Organic Light Emitting Diodes (OLEDs) Materials.

Published online by Cambridge University Press:  01 February 2011

Z. T. Liu
Affiliation:
Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
C. C. Oey
Affiliation:
Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
A. B. Djuriši
Affiliation:
Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
C. Y. Kwong
Affiliation:
Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
C. H. Cheung
Affiliation:
Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
W. K. Chan
Affiliation:
Department of Chemistry.The University of Hong Kong, Pokfulam Road, Hong Kong
P. C. Chui
Affiliation:
Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
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Abstract

In this work, optical functions of some widely used OLEDs materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), tris (8-hydroxyquinoline) aluminum (Alq3), (N,N′-di(naphthalene-1-yl)-N,N′- diphenylbenzidine (NPB),poly(3,4,-ethylene dioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) and indium tin oxide (ITO)) were studied using spectroscopic ellipsometry (SE) in the spectral range from 1.55 eV to 4.1 eV (wavelength range of 300 nm to 800 nm). The samples were prepared either by thermal evaporation in high vacuum or spin-coating of thin films onto glass substrates. For determination of the optical functions of ITO, commercial ITO glass was used. Measurements at different incident angles were performed to determine whether the samples can be considered isotropic. The SE data were modeled using an oscillator model (Lorentz for semiconducting and Lorentz-Drude for conducting materials). The absorption spectra were also measured, and the comparison with the data determined by SE is given.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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