Title :
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
Abstract :
We discuss several device architectures leading to high-efficiency organic electrophosphorescent (EP) light emission. An external electroluminescence efficiency (ηext) 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;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/2944.999192
