Improved efficiency by a graded emissive region in organic light-emitting diodes

被引：82

作者：

Ma, DG

Lee, CS

Lee, ST

Hung, LS ^{[1
]}

机构：

[1] City Univ Hong Kong, COSDAF, Hong Kong, Hong Kong, Peoples R China

[2] City Univ Hong Kong, Dept Phys & Mat Sci, Hong Kong, Hong Kong, Peoples R China

[3] Chinese Acad Sci, Changchun Inst Appl Chem, Changchun 130022, Peoples R China

来源：

APPLIED PHYSICS LETTERS | 2002年 / 80卷 / 19期

关键词：

D O I：

10.1063/1.1479450

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Electrical and optical properties of organic light-emitting diodes (OLEDs) with a stepwise graded bipolar transport emissive layer for a better control of charge transport and recombination are presented. The graded bipolar transport layer was formed by co-evaporating a hole-transporting material N,N-'-diphenyl-N,N-'-bis(1,1(')-biphenyl)-4,4(')-diamine (NPB) and an electron-transporting/emissive material tris-(8-hydroxyquinoline) aluminum (Alq(3)) in steps, where each step has a different concentration ratio of NPB to Alq(3). Compared to a conventional heterojunction OLED, electroluminescence efficiency was enhanced by a factor of more than 1.5, whereas the turn-on voltage remained unchanged in the graded structure. (C) 2002 American Institute of Physics.

引用

页码：3641 / 3643

页数：3

共 13 条

[1] Degradation mechanism of small molecule-based organic light-emitting devices [J].