Synthesis, photophysical and electro-optical properties of bis-carbazolyl methane based host material for pure-blue phosphorescent OLED

A new high triplet-energy host material, 9-(4-(bis(9-ethyl-9H-carbazol-3-yl)methyl)phenyl)-9H-carbazole (bis-CMPC), was synthesized and its device performance of phosphorescent organic light-emitting diode was investigated. This host material showed a high triplet energy (∼2.95 eV) and good thermal stability. Highly efficient pure-blue PHOLED was obtained when employing bis-CMPC as the host material and bis((3,5-difluoro-4-cyanophenyl)pyridine) iridium picolinate as the guest material. The maximum external quantum efficiency of the device reached as high as 13.3% with a pure-blue color coordinate of (0.14, 0.21).