Carboline derivatives with an ortho-linked terphenyl core for high quantum efficiency in blue phosphorescent organic light-emitting diodes

Two host materials, 9-(3''-(9H-carbazol-9-yl)-[1,1':2',1''-terphenyl]-3-yl)-α-carboline (CzOTCb) and 3,3''-bis(α-carbolin-9-yl)-1,1':2',1''-terphenyl (CbOTCb), derived from carboline and ortho-linked terphenyl were synthesized as high triplet energy materials and showed a high triplet energy of 2.90 eV. CzOTCb and CbOTCb were evaluated as the host materials for blue phosphorescent organic light-emitting diodes and high quantum efficiencies of 27.4% and 28.8% were obtained using the CzOTCb and CbOTCb hosts, respectively.