主链含芳基氧膦单元的高三线态双极高分子主体的设计、合成与电致发光性能

The development of blue phosphorescent polymer light-emitting diodes (PhPLEDs) is substantially hindered by the low triplet energies and unbalanced carrier transport capabilities of their hosts. In this project, we attempt to break through the limitation of the currently known polymer hosts. We propose a novel kind of polymer main chains based on aryl phosphine oxide units which possess high triplet energies and electron transport capabilities, meanwhile, carbazole dendrons are introduced into the polymer side chains to transport holes.This molecular design is aiming at harmonizing triplet energy levels and ambipolar characteristic of the polymer hosts. The objectives of this project is to develop a novel series of polymer hosts which possess both high triplet energies and bipolar injection/transport capabilities, which ensures the fabrication of high-efficiency multilayer- and single-layer blue PhPLEDs and all-phosphorescent white PhPLEDs.

现有高分子主体材料存在三线态能级低和载流子传输不平衡的缺点，严重阻碍了蓝色磷光高分子电致发光器件的发展。本项目旨在突破现有高分子主体的这些限制，以芳基氧膦单元为基础构造具有电子传输能力的高三线态主链，同时在侧链引入具有空穴传输能力的咔唑树枝，来实现对三线态能级和载流子注入/传输能力的协同调控，目标在于开发一类结构新颖的、兼具高三线态能级和优异双极传输特性的高分子主体材料，从而为组装高效蓝色磷光和全磷光白光高分子器件提供材料保障。

针对现有高三线态高分子主体材料匮乏严重制约蓝光磷光高分子电致发光器件的发展这一瓶颈问题，本项目旨在突破现有高分子主体的三线态能级限制，以芳基氧膦单元为基础构造新型的、具有高三线态能级和双极性特点的高分子主体材料。项目通过对聚（芳基氧膦）高分子主体的主链、侧链以及连接单元结构修饰，揭示了其化学结构、能级结构以及电学性质关系，实现了三线态能级与HOMO能级的协调调控。在材料方面，获得了具有“宽三线态调控窗口”、“高HOMO能级”、“HOMO/LUMO分离”等特色的系列高分子主体材料。在器件方面，基于溶液加工工艺制备出覆盖全可见光光谱、具有高外量子效率、低驱动电压、低效率衰减等单项指标突出、综合性能优秀的高分子磷光器件。其中，三基色（蓝、绿、红）高分子磷光器件的外量子效率分别达到15.9 %、15.8 %和10.8 %；白光高分子磷光器件的功率效率达到44.9 lm/W，已接近基于真空蒸镀工艺的小分子白光磷光器件的效率水平。