咔唑类衍生物具有良好的空穴传输性能和较高的三重态能级,在有机电致发光器件中一般用来构建空穴传输材料和主体材料.本文通过在联咔唑的3和6位引入具有电子传输能力的氰基,设计合成了一种以双咔唑二聚体为分子骨架的新型双极性有机电致发光主体材料6,6'-双氰基-9,9 '-二苯基-3,3 '-联咔唑(BCzDCN),研究了其发光性能、热稳定性和电化学性质.低温磷光发射光谱测试表明BCzDCN的三重态能级高于传统的天蓝色磷光掺杂材料双(4,6-二氟苯基吡啶-N,C2 ')吡啶甲酰合铱(FIrpic).以BCzDCN为主体材料,FIrpic和双(4-苯并噻吩[3,2-C])吡啶-N,C2)乙酰丙酮合铱(PO-01)分别为蓝色和黄色磷光掺杂材料,制备了蓝色和白色有机磷光发光二极管器件.器件的最大电流效率分别达到34.6 cd/A和59.0 cd/A.并且在1000 cd/m2亮度下的效率滚降仅有4.1%和5.1%.
Carbazole derivatives are usually used as hole transport and host materials because of their good hole transport ability and high triplet energy.In this paper,a novel bicarbazole derivative,named BCzDCN,was designed and synthesized by incorporating electron-withdrawing cyano group into bicarbazole at 3,6 position.Its thermal,photophysical and electrochemical properties were systematically investigated.The triplet energy of BCzDCN is higher than that of the most popular blue phosphorescent material iridium(Ⅲ) bis[(4,6-difluorophenyl) pyridinato-N,C2'] picolinate (FIrpic).Therefore BCzDCN could be used as host material for blue phosphorescent organic light-emitting diodes (PHOLEDs) and further for white PHOLEDs.Blue and White PHOLEDs using BCzDCN as host exhibited excellent performance with maximum current efficiencies of 34.6cd/A and 59.0 cd/A,respectively.Meanwhile,both the blue and white PHOLEDs exhibited extraordinary low efficiency roll-offs,their efficiencies roll-offs were merely 4.1% and 5.1% at the brightness of 1000 cd/m2,respectively.