新型圆偏振发光的热活性延迟荧光材料的设计、合成与电致发光性能研究

Electroluminescence materials is a hot topic in the research of organic optoelectronic functional materials. The organic light-emitting diodes, however, prepared by these materials are used to added a polarizer and a quarter-wave plate for the attenuation of the external light reflection to achieve higher image contrast, which cause light lost. As the third generation luminescence materials, thermally activated delayed fluorescence (TADF) materials can harvesting triplet excitons to achieve nearly 100% interal quantum efficiency without containing any noble matels, are considered as the most potential luminescence materials. However, their OLEDs still encounter the light lost by the use of polarizers.. The circularly polarized luminescence TADF emitters may resolve these problems. Therefore, developing circularly polarized luminescence TADF materials are of great interesting. The research of these type materials is just beginning and far lag behind. This project is to design and synthesis of new chiral TADF materials by connect the TADF molecules with a chiral molecules or design new chiral donors or acceptors. The thermally activated delayed fluorescence materials will enabling circularly polarized light emission through chiral perturbation. Investigation of the electroluminescence properties of these chiral materials and the conditions of the preparation of relevant devices. Finally, obtain high-performance circularly polarized electroluminescence materials and devices.

电致发光材料是目前有机光电功能材料的研究热点之一。由当前材料制备的OLEDs往往需要使用偏振片和1/4波片来获得更高的图像对比度，偏振片对光的吸收增加了光损耗。作为第三代发光材料，热活性延迟荧光（TADF）材料不含贵金属却依然利用了三重态激子，理论内部量子效率可达100%，是公认的最具潜力的发光材料之一，然而其也存在器件必须牺牲光损耗来获取更高图像对比度的问题。. 将TADF分子设计成电致发射圆偏振光的材料可有效解决偏振片的吸收问题，但相关研究依然非常滞后。本项目在分子设计与合成上深化对该类分子的研究。分别通过向TADF分子中引入手性源分子或将给体、受体设计成手性的分子，再分别与非手性的受体或给体结合，得到绝对构型的TADF分子，同时手性中心能够诱导TADF分子发射圆偏振光。研究这些手性分子的电致发光性能，以及相关器件制备的优化条件，最终获得高性能的圆偏振发光材料及器件。

针对圆偏振发光的热活化延迟荧光（TADF）材料还存在分子结构少、研究多集中在绿光而其它光色的研究还很滞后、缺乏手性给体等科学问题，本项目通过三种策略设计并合成了手性的红光、绿光和蓝光材料，并进一步表征了这些材料的分子结构，研究了它们的电学、热学、光物理以及电致发光等性能。所合成的手性分子大多表现出优异的TADF性能，而且具有较明显的圆偏振发光特性，实现了红绿蓝三色光的全覆盖。开发的红光材料不仅实现了高达20.5%的最大外量子效率，而且获得了至今为止基于TADF材料最大的不对称因子0.38。本研究为开发兼具高效率和高不对称因子的发光材料和器件提供了重要的分子设计依据。