基于咔唑-三唑的新型主体材料及天蓝光有机电致磷光器件

本研究针对蓝光主体材料相对缺乏的现状,利用有机电致磷光器件高效率的优势,选择1,2,4-三唑为电子传输功能基团、咔唑为空穴传输功能基团,设计、制备了新型主体材料oCzTz。通过邻位取代方式实现了分子立体构型高度扭曲,从而使分子的三重态能量达到3.01eV;oCzTz具有较高的热分解温度(353℃)和玻璃化转变温度(110℃);量化计算显示,分子的前线轨道在咔唑和三唑基团之间高度分离。以oCzTz为主体、以FIrpic为发光客体的天蓝光电致磷光器件启亮电压为3.4V,电流效率和功率效率分别高达37.2cd·A-1和29.2lm·W-1,是以TPBI为电子传输层的同类器件的最高效率之一。

Novel Trizazole-carbazole Based Host Material for Sky-blue Electrophosphorescent Devices

Phosphorescent organic light-emitting diodes (OLEDs) are advantageous over the traditional fluorescent ones in terms of high efficiency by harvesting both singlet and triplet excitons for light emission.Transition-metal complex phosphors must be dispersed in a certain host matrix to suppress the concentration quenching and triplet-triplet annihilation.Therefore,the host material is as important as the dopant emitter in phosphorescent OLEDs.In this report,a novel host material,oCzTz,was developed by using 1,2,4-triazole as the n-type unit and carbazole as the p-type unit.Ortho-substitution was applied to reach a twisted molecular configuration,which finally leads to high triplet energy of 3.01 eV for oCzTz.oCzTz has high thermal decomposition temperature of 353 ℃ and glass transition temperature of 110 ℃.The theoretical calculation results showed that the HOMO and LUMO are highly separated,indicating its bipolar charge transporting feature.oCzTz was used as host material to fabricate sky-blue phosphorescent OLED with Flrpic as the doped emitter,which exhibited a low turn-on voltage of 3.4 V,the high current efficiency of 37.2 cd · A-1 and the power efficiency of 29.2 lm · W-1.These are one of the highest efficiencies among the sky-blue phosphorescent OLEDs with TPBI as electron transporting layer.