热活化延迟荧光材料薄膜聚集态结构调控及其电致发光性能研究

The electroluminescent performance of the thermally activated delayed fluorescence (TADF) materials is related to the morphology of the films. It’s important to tune the morphology and electroluminescent performance of the TADF films by physical methods and establish the correlation between the morphology and electroluminescent performance of the TADF films. This project is proposed to study the morphology of thermally activated delayed fluorescence materials and its correlation to the electroluminescent performance to develop the preparation methods of highly efficient TADF electroluminescent films and establish the correlation between the morphology and electroluminescent performance of the TADF films. The details include as follows: (1) Optimizing the morphology of TADF polymer films by tuning the solution state and investigating its effect on photophysics (such as the ΔEST and the photoluminescent quantum efficiencies), charge carrier transport property and the electroluminescent performance. (2) Investigating the effect of film preparation methods on the morphology and TADF electroluminescent performance of the exciplex films. (3) Establishing the correlation between the morphology and electroluminescent performance of the TADF films to provide effective approaches to prepare highly efficient TADF electroluminescent device.

热活化延迟荧光(TADF)材料的电致发光行为与TADF发光薄膜的聚集态结构密切相关。通过物理手段调控TADF发光薄膜聚集态结构及性能，建立TADF发光薄膜聚集态结构与发光性能的构效关系是亟待解决的关键问题。本项目拟开展TADF发光薄膜聚集态结构调控及其电致发光性能的研究，开发高效率TADF发光薄膜的制备方法，构建较明确的TADF发光薄膜聚集态结构与电致发光行为的构效关系。研究内容包括：(1)针对TADF高分子通过调节溶液状态和溶剂性质调控TADF薄膜的聚集态结构，研究其对ΔEST能级及荧光量子效率等薄膜光物理和载流子传输性质以及最终器件发光性能的影响。(2)针对激基复合物型TADF体系，研究不同的薄膜制备方式对薄膜聚集态结构和TADF发光器件性能的影响。(3)建立TADF发光薄膜聚集态结构和器件电致发光性能的构效关系，为制备高效率TADF型有机电致发光器件提供有效的实施途径。

热活化延迟荧光(TADF)材料的电致发光行为与TADF发光薄膜的聚集态结构密切相关。调控TADF型激基复合物发光薄膜聚集态结构，建立TADF发光薄膜聚集态结构与发光性能的构效关系，提高效率、降低效率滚降是器件满足实际应用亮度亟待解决的关键问题。本项目我们系统分析了由给、受体材料形成的激基复合物共混薄膜凝聚态结构、光物理行为和器件电致发光性能之间的对应关系。通过共混绝缘聚合物，改变给受体比例和构筑共晶调控激基复合物共混薄膜凝聚态结构，提高电致发光性能。主要研究内容包括：（1）激基复合物中共混绝缘聚合物分散给、受体分子，增加反向系间窜越速率，使溶液加工型OLED电致发光效率提高，效率roll-off降低。（2）改变给、受体比例调控延迟荧光寿命，进而调控电致发光效率及效率滚降，实现了10000 cd m-2下6.74%的外量子效率。（3）将调控给、受体比例应用到激基复合物为主体敏化传统红光荧光材料体系中，过量给体极大地减少了激基复合物的浓度猝灭效应与从激基复合物到荧光材料的Dexter能量转移，使敏化器件外量子效率提高。（4）通过构筑激基复合物共晶，降低非辐射跃迁速率，增加反向系间窜越速率，使电致发光器件外量子效率提高，同时激基复合物共晶体系刚性，抑制分子振动和转动，降低发光光谱半峰宽。在科研成果产出方面，截止撰写结题报告当前，共发表SCI 论文5篇，中文核心1篇。我们完成了项目申请期间拟定的预设研究目标。