Architectures for efficient electrophosphorescent organic light-emitting devices

Author

Adachi, Chihaya ; Thompson, Mark E. ; Forrest, Stephen R.

Author_Institution

Dept. of Electr. Eng., Princeton Univ., NJ, USA

Volume

8

Issue

2

fYear

2002

Firstpage

372

Lastpage

377

Abstract

We discuss several device architectures leading to high-efficiency organic electrophosphorescent (EP) light emission. An external electroluminescence efficiency (η_ext) of (10.0 ± 0.5) % was realized by doping fac-tris(2-phenylpyridine)iridium (Ir(ppy) ₃) into a 2,9-dimethyl-4,7-diphenyl-1,10-phenenthroline (BCP) electron transport layer. Direct exciton formation on the phosphor dopant avoids exciplex formation at the interface of unipolar hole and electron transport layers. Further, triplet exciton and carrier dynamics in a double heterostructure were investigated to determine the location and width of the exciton formation zone. High-efficiency EP is also demonstrated in a simplified two layer architecture using a 4,4´-N, N´-dicarbazole-biphenyl (CBP) ambipolar carrier transport host

Keywords

electron mobility; excitons; light emitting diodes; organic compounds; phosphorescence; 10 percent; 2,9-dimethyl-4,7-diphenyl-1,10-phenenthroline; 4,4´-N, N´-dicarbazole-biphenyl; ambipolar carrier transport host; carrier dynamics; device architecture; direct exciton formation; doping; double heterostructure; electron transport layer; electron transport layers; electrophosphorescent organic light-emitting devices; exciplex formation; exciton formation zone; external electroluminescence efficiency; high-efficiency organic electrophosphorescent light emission; phosphor dopant; triplet exciton; unipolar hole transport layers; Doping; Electroluminescence; Excitons; Lead compounds; Materials science and technology; Organic light emitting diodes; Phosphorescence; Phosphors; Photonics; Temperature;

fLanguage

English

Journal_Title

Selected Topics in Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

1077-260X

Type

jour

DOI

10.1109/2944.999192

Filename

999192