High-efficiency deep-blue-phosphorescent organic light-emitting diodes using a phosphine oxide and a phosphine sulfide high-triplet-energy host material with bipolar charge-transport properties

Highly efficient deep-blue-phosphorescent organic light-emitting diodes have been developed using bipolar-type high-tripletenergy host materials with a carbazole core and two phosphine oxide (PPO21) or phosphine sulfide (PPS21) units. A high quantum efficiency of 19.2% with a deepblue color coordinate of (0.14,0.16) was achieved in the deep-blue device with PPO21 as a host material (see figure). (Fig. Represented)