3,3′-Bicarbazole-Based Host Materials for High-Efficiency Blue Phosphorescent OLEDs with Extremely Low Driving Voltage

Four types of functionalized 3,3'-bicarbazole derivatives are prepared and investigated as a host material for blue phosphorescent OLEDs. By using a 3,3'-bicarbazole derivative/FIrpic film as an emissive layer, high power efficiency of 46 lm W-1 (45 cd A(-1), EQE 20%) with an extremely low driving voltage at 3.1 V is obtained at 100 cd m(-2).