High-efficiency nondoped white organic light-emitting devices

High-efficiency nondoped white organic light-emitting devices (WOLEDs) were demonstrated by using both the intrinsic and exciplex emissions from a single electroluminescent material, 4,4('),4(')-trispyrenylphenylamine (TPyPA). The simple device structure of indium tin oxide/N,N-'-bis(1-naphthyl)-N,N-'-diphenyl-1,1(')-biphenyl-4,4(')-diamine/TPyPA/4,7-diphenyl-1,10-phenanthroline/LiF/Al exhibited a luminance of 10 000 cd/m(2) at a low driving voltage of 4.5 V, and high current and power efficiencies of 9.4 cd/A and 9.0 lm/W, respectively. Such WOLED showed excellent color stability and purity with the Commission Internationale de L'Eclairage coordinates of (0.31, 0.35), which remained unchanged over a wide range of luminance from 100 to 20 000 cd/m(2). (C) 2007 American Institute of Physics.