A novel benzo[4,5]furo[3,2-d]pyrimidine-based host as a n-type host for blue phosphorescent organic light-emitting diodes

An electron-transport-type host was synthesized using a benzo[4,5]furo[3,2-d]pyrimidine (BFP) core to develop a high triplet energy host. The host was designed to have both the tetraphenylsilyl blocking group and the hole-transport-type carbazole group. In the device application, the host was used as an electron-transport-type host mixed with a hole-transport-type 3,3†-di(9H-carbazol-9-yl)-1,1†-biphenyl (mCBP) host in the blue phosphorescent organic light-emitting diodes (PhO-LEDs) doped with a [[5-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]bis-[[6-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]iridium (Ir(cb)₃) blue phosphor. As a result, the mCBP:CzBFPmSi mixed host showed high external quantum efficiency over 20% at 1000 cd m⁻² and low efficiency roll-off in the blue PhOLEDs.