A thermally stable bipolar host material for blue phosphorescent organic light-emitting diodes

A dibenzofuran based host material, 9,9′-(4-(diphenylphosphoryl)dibenzo[b,d]furan-2,8-diyl)bis(9H-carbazole) (DBFDCzPO), was developed as a thermally stable high triplet energy host material for blue phosphorescent organic light-emitting diodes (PHOLEDs). DBFDCzPO showed high triplet energy of 2.89 eV and stable film morphology up to 130 °C. DBFDCzPO was compared 2,8-di(9H-carbazol-9-yl)dibenzo[b,d]furan and exhibited better device performances. A high quantum efficiency of 17.6% was achieved in the blue PHOLEDs using the DBFDCzPO host material.