High efficiency and simple architecture phosphorescent OLEDs

We present an ideal host-guest concept for highly efficient phosphorescent OLEDs (PHOLEDs). Highly efficient PHOLEDs with an extremely low doping concentration of 1% are developed. The origin of such a low doping is revealed by energy transfer mechanism studies and ideal host-guest concept. Simple architectures for PHOLEDs are realized based on this ideal host guest concept. Organic bi-layered and triple-layered architectures for PHOLEDs with high efficiency are reported. Results reveal a practical way to fabricate the highly efficient simple structure devices for trouble-free manufacturing processes.