高效长波长热活化延迟荧光材料的合成及光电性能研究

In recent years, thermally activated delayed fluorescence (TADF) materials have been a new research hotspot in the field of organic light-emitting diodes (OLEDs). Compared with traditional fluorescent and phosphorescent emitters, TADF emitters can not only realize 100% internal quantum efficiency, but also have the advantages of low cost and environmental friendliness, which are considered as the next generation organic flat panel display and lighting materials. With the rapid development of TADF materials and devices, the external quantum efficiency (EQE) of blue, green and yellow TADF-OLEDs has been comparable to those of the state-of-the-art phosphorescent OLEDs reported. However, high performance long-wavelength TADF emitters are still very rare, and their device performance is still lag far behind that of blue, green and yellow OLEDs. In addition, most of TADF-OLEDs suffer serious efficiency roll-off at high current density. Therefore, the development of TADF-OLEDs with high efficiency and low efficiency roll-off is very important for the practical application. This project focuses on the development of highly efficient and low roll-off long-wavelength TADF-OLEDs by using coumarin as acceptor unit. Through systematically studying materials properties, we aim to elucidate the relationship between molecular structure and device performance, and provided theoretical support for the further development of highly efficient long-wavelength TADF materials.

近年来，热活化延迟荧光（TADF）材料已经逐渐成为有机发光二极管（OLEDs）领域研究的新热点。与传统荧光和磷光材料相比，TADF材料不仅能够实现100%的内量子效率，而且具有成本低、环境友好等优势，因此被视为下一代有机平板显示和照明材料。随着TADF材料和器件的快速发展，基于TADF机制的蓝光、绿光和黄光器件外量子效率（EQE）已接近甚至超过磷光器件的水平。然而，目前高性能长波长TADF材料还很缺乏，其器件性能远远落后于蓝光、绿光和黄光。此外，大部分TADF器件在高电流密度下表现出了较为严重的效率滚降。因此，设计开发高效率、低滚降的长波长TADF器件具有十分重要的现实意义。本项目拟利用氰基取代香豆素作为受体基团构筑新型的TADF体系，致力于实现高效率低滚降的长波长TADF器件。通过对材料性质的系统研究，阐明材料分子结构与性能的关系，为进一步开发新型高效的长波长TADF材料提供理论支持。

近年来，热活化延迟荧光（TADF）材料由于具有成本低、环境友好、能实现100%内量子效率等优势，已经受到了学术界和工业界的广泛关注。相对于快速发展的蓝光、绿光TADF材料，长波长TADF材料还很缺乏，器件性能仍相对落后。基于此，本项目针对长波长TADF材料存在的一些关键科学问题进行了系统研究，并取得了系列研究进展，主要成果如下：1、设计开发了系列以氰基取代香豆素为受体的长波长TADF材料，系统探究了该类材料分子结构和发光性能的构效关系，但制备的电致发光器件效率仍有待提升。2、基于喹喔啉受体构建长波长TADF材料，通过对分子结构和聚集态结构的协同优化，成功获得了具有高效率的橙红至近红外TADF材料。基于该类TADF材料制备的各色长波长OLED器件效率均达到了当前国际先进水平。到目前为止，以第一或通讯作者身份在Angewandte Chemie International Edition（1篇）、Advanced Functional Materials（4篇）、Advanced Optical Materials（1篇）、The Journal of Physical Chemistry Letters（1篇）等国际著名学术期刊上发表标注本基金号的高水平研究论文12篇。项目运行期间，申请中国发明专利6项，培养研究生7名。