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/ LiFAl exhibited a luminance of 10 000 cd m2 at a low driving voltage of 4.5 V, and high current and power efficiencies of 9.4 cdA and 9.0 lmW, 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 m2. © 2007 American Institute of Physics.link_to_subscribed_fulltex