不对称p-n型双极主体材料及其蓝色电致磷光器件研究

Organic light-emitting diodes (OLEDs) are considered as an emerging technology for the next generation of ultra-thin flat panel displays. The issue of the blue phosphorescent organic light-emitting diodes (PhOLEDs) with low efficiency is one of challenge for the development of the OLEDs at the moment. To further improve the performance of the PhOLEDs，a series of blue host materials with bipolar characters will be designed and synthesized on the basis of triazine acceptor by chemical approach in this project. Combining the measurements of the electroluminescence devices with the theoretical calculations, the relationship of the molecular structures, electronic structures and device performance will be systematically investigated to reveal the influence of electronic structures of host materials on the processes of the triplet-triplet annihilation and the triplet-polaron quenching in emitting layer, including the spatial distribution, ratio and constituents of the generated singlet and triplet excitons as well as the orientation of the molecular transition dipole moments. It is of important significance for the development of blue PhOLEDs with high efficiency to break through the bottleneck of organic electroluminescent diodes.

有机电致发光二极管是下一代超薄平板显示器新兴应用技术，但是低效蓝光电致磷光器件是制约其发展的瓶颈之一。本项目拟针对这一问题，采用化学修饰策略，以受体单元三嗪为前驱体，设计合成一系列高三线态能级双极蓝光主体材料，进而制备并改善电致发光器件性能。通过电致发光器件性能表征和理论模拟计算，探索主体材料分子结构、电子结构与器件性能的内在关系。研究主体材料分子的单线态激子与三线态激子的分布区域、比例关系、电子成分（局域激发态和电荷转移激发态）以及主-客体材料分子偶极矩取向情况对器件性能的影响规律，揭示主体材料分子的电子结构与电致发光器件中的三线态-三线态湮灭和三线态-极化子猝灭过程的关系。本项研究将对高效蓝光电致磷光器件的开发具有重要理论指导意义，突破目前有机电致发光二极管的瓶颈。

本项目围绕双极主体材料的设计与合成，通过光物理性能表征，阐明分子构建单元对主体材料的成膜性、热力学性质、发光性质、前线轨道能级以及激发态能级的影响规律，获得高效率的蓝色电致发光器件为目标展开研究。前期研究进展顺利，获得外量子效率为12.6%的电致发光器件。项目实施期间，我们发现的设计的基于咔唑与三嗪单元的主体材料表现出超长寿命的磷光发射，即有机长余辉发光。因此后期研究了这类主体材料的有机长余辉发光性质，并探索了其在数据加密、防伪与生物成像的应用。