High-efficiency blue phosphorescent organic light-emitting diodes using a carbazole and carboline-based host material

A novel bipolar host 9-(4-(9H-pyrido[2,3-b]indol-9-yl)phenyl)-9H-3,9'-bicarbazole (pBCb2Cz) was prepared for high efficiency blue phosphorescent organic light-emitting diodes (PhOLEDs), a high triplet energy (ET) material, employing electron-deficient alpha-carboline. pBCb2Cz (E-T = 2.93 eV) was effective as a host material for FIrpic- and FCNIrpic-based blue PhOLEDs, and highest quantum efficiencies of 23.0 and 16.2%, respectively, were achieved.