Twisted biaryl-amines as novel host materials for green-emissive phosphorescent organic light-emitting diodes (PhOLEDs)

Insertion of rigid biaryl moieties, namely, 2,2',6,6'-tetramethylbiphenyl and 2,2',6,6'-tetramethoxylbiphenyl, between two phenyl rings of CBP leads to novel host materials with improved thermal stabilities (T(g)s similar to 111-148 degrees C). Their high triplet energies (2.63-2.83 eV) permit application as host materials for green phosphors, i.e., Ir(ppy)(3). External quantum efficiency and brightness of the order of ca. 15% and ca. 6000 cd m(-2) have been realized with TetMeTPA and TetOMeCZL, respectively.