摘要:本项工作开发了一种具有热激子性质的激发态分子内质子转移(Excited-State Intramolecular Proton Transfer, ESIPT)橙光材料HBT-TPA,该材料以2-(2'-羟基苯基)苯并噻唑(HBT)作为ESIPT单元,修饰以强给电子基团三苯胺(TPA),赋予材料一定的电荷转移特性,使分子的醇式和酮式异构体激发态均呈现出混合局域电荷转移态(Hybridized Local and Charge Transfer State, HLCT)性质。以HBT-TPA为发光材料制备的OLED器件呈现出橙光发射,其电致光谱的发光峰位于576 nm,对应的国际发光委员会(Commission Internationale de l´Eclairage, CIE)色坐标为(0.5007±0.0016,0.4883±0.0008)。器件的最大外量子效率及最大电流效率分别为2.0 %和5.0 cd/A,并获得了29.3%–43.9%的激子利用率。器件中较为高效的激子利用率是利用ESIPT发光材料中的酮式异构体通过高能级反向系间窜越(High-lying Reverse Intersystem Crossing, hRISC)的热激子机制来实现的。
“In the field of organic light-emitting diodes (OLEDs), two tetrasubstituted carbazole derivatives TBICz and TOXDCz have been designed and synthesized, exhibiting excellent thermal and morphological stabilities. Utilizing these novel compounds as host materials, high efficiency solution-processed green phosphorescent organic light-emitting diodes (PhOLEDs) have been achieved. The best EL performance is achieved for the TBICz-based device, providing more host material options for solution-processed OLEDs.”