Efficient and color stable phosphorescent white organic light-emitting devices based on an ultra wide band-gap host

摘要

We report high efficiency phosphorescent white organic light-emitting devices (WOLEDs) employing single emissive layer (EML) based on an ultra wide band-gap host. Effective exciton/charge confinement and balanced recombination within EML was achieved by employing adequate interlayer and stepwise hole-transporting layer (step HTL) system. Moreover, this step HTL system lower driving voltage of WOLEDs, therefore power efficiency was enhanced over 40 percent. These WOLEDs showed external quantum, and power efficiencies of 17.6 percent, and 37.5 1m/W at 100 cd/m~2 without outcoupling enhancements. We also found that these WOLEDs exhibited little change of color coordinate from 100 to 10,000 cd/m~2.