A novel spiro-annulated benzimidazole host for highly efficient blue phosphorescent organic light-emitting devices

A novel host material featuring a spiro-annulated benzimidazole configuration is exploited for blue phosphorescent organic light-emitting devices (PhOLEDs). The new material exhibits a high triplet energy (3.07 eV) and a bipolar characteristic and is effective as the host for FIrpic-, FIr6- and FK306-based blue PhOLEDs with high performances.