Interface formation between NPB and processed indium tin oxide

被引:48
作者
Le, QT
Forsythe, EW
Nüesch, F
Rothberg, LJ
Yan, L
Gao, Y
机构
[1] Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA
[2] Univ Rochester, Dept Chem, Rochester, NY 14627 USA
基金
美国国家科学基金会;
关键词
indium tin oxide; X-ray photoelectron spectroscopy; ultraviolet photoelectron spectroscopy;
D O I
10.1016/S0040-6090(99)00979-7
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We have investigated the interface formation between ITO and N,N'-bis-(1-naphthyl) -N,N'-diphenyl- 1,1 '-biphenyl-4,4'-diamine (NPB), an organic materials often used as hole transport layer in organic light-emitting devices (OLED), by using X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) and atomic force microscopy (AFM?). Acid or base treatment of indium tin oxide (ITO) surfaces can significantly alter the surface work function which, in the case of acid treatment, points to an improved energy level alignment with NPB and, therefore, enhanced hole injection efficiency. We found no significant reactions nor level bending for NPB deposited on standard ITO. In contrast, for acid-heated ITO, reaction of NPB nitrogen with the proton of the dipole layer on the ITO surface is observed. At low NPB coverages, AFM images reveal uniform island growth of NPB on ITO. Further deposition leads to a more complete covering of the ITO surface by NPB layer, corresponding to a laminar growth mode. (C) 2000 Published by Elsevier Science S.A. AU rights reserved.
引用
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页码:42 / 46
页数:5
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