Triphenylene-based host materials for low-voltage, highly efficient red phosphorescent organic light-emitting diodes

Triphenylene-based host materials BDBF-TP and BDBT-TP were synthesized for use in red phosphorescent organic lightemitting diodes (PHOLEDs). The currentvoltage characteristics of hole- and electron-only devices revealed that BDBT-TP exhibits better bipolar carrier transport properties than 4,4'- bis(carbazol-9-yl)-1,1'-biphenyl and BDBF-TP. Red PHOLEDs containing BDBF-TP or BDBT-TP as the host showed a lower driving voltage, higher external quantum efficiency, and lower efficiency roll-off at high current density.