Bis(4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)dimethylsilane as Electron-Transport Material for Deep Blue Phosphorescent OLEDs

Abstract

Bis(4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)dimethylsilane (SiTAZ) was designed and synthesized as an electron-transporting material for deep blue phosphorescent organic light-emitting devices (PHOLEDs). Introducing a Si atom between two 3,4,5-triphenyl-1,2,4-triazole molecules, a high triplet energy of 2.84 eV, high glass transition temperature of 115 °C, and high electron mobility of 6.2 × 10−4 cm2 V−1 s−1 were achieved. By employing SiTAZ as a hole-blocking and electron-transporting material of iridium(III)[bis(4,6-difluorophenyl)pyridinato-N,C2′]tetrakis(1-pyrazolyl)borate (FIr6)-based deep blue phosphorescent OLEDs, a maximum external quantum efficiency (EQE) of 15.5%, an EQE of 13.8% at high luminance of 1000 cd m−2, and deep blue color coordinates of (0.16, 0.22) were achieved. The reduced efficiency roll-off at high luminance was attributed to the high triplet energy of the SiTAZ.