可溶液加工型自掺杂热活化延迟荧光蓝色发光体的合成及其器件性能的优化

On account of the advantages of organic electroluminescent materials compared with their inorganic counterparts, the development of organic electroluminescent materials is one of the hot areas of the optoelectronic information materials. Among the three basic color, blue, red and green, for full color display, the efficiency, color purity and life-time of the former two have fully met the requirements of commercialization, while the blue light is still lagging behind the former two, which has been a troublesome bottle-neck strongly puzzling the academic and industry partnerships. Especially, the performance and efficiency of the blue-light emitting devices are critically dependent on the materials development, device design, deposition processes, and modeling, among which the active materials of organic semiconductor play a crucial role. Because they are thought as a great breakthrough in improving the external quantum efficiency of the conventional organic light-emitting diode, thermally-activated delay fluorescence technologies have become an active research topic of organic electronic in recent years. This project suggests the synthesis and device optimization of solvent-processable and self-doped electroluminescent blue-light emitters based-on thermally-activated delay fluorescence, in which typical electron-rich carbazole-related units and electron-deficient phosphine oxide or sulfone-related units are incorporated into one molecule by Suzuki or other cross-coupling reaction. By adjusting the type, conjugation lengths and molecular regiochemistry of the above-mentioned segments, the topology-varied polymers and oligomers can be easily obtained, which serve as the optimum object to correlate the relationship between molecular structures and light-emitting properties. Through effective organic synthesis, precise adjustment of light-emitting properties in a wide range, excellent device performance and insightful density functional theory calculations, we expect to obtain blue-light emitting diodes with external quantum efficiency as high as 10%. The set up of the project will provide strong technological support for the advance of the polymer light-emitting diodes in the near future.

热活化延迟荧光是一种利用热作用下三线态激子到单线态激子的反转来提高材料发光效率的新技术。本项目利用具有不同电性能和能级结构的芳环取代膦氧单元、咔唑和芳香环砜类衍生物等作为主要桥联基团，合成一系列具有分子内电荷转移特征的可溶液加工型自掺杂热活化延迟荧光蓝色发光体。详细研究热活化延迟荧光蓝色发光体的合成路线，探索温度和反应物配比等反应条件对产物纯度和产率的影响。研究桥联基团的种类、取代位置以及分子拓扑结构的多样化对材料的能级、共轭长度、热稳定性和光物理性质的影响，进而独立调节其热稳定性、载流子迁移率和能级结构等指标参数，得到具有自搀杂特征的可溶液加工型热活化延迟荧光蓝色发光体。得到外量子效率大于10%的高效稳定电致蓝光器件，系统研究可溶液加工、自掺杂和热活化延迟荧光三重策略在提高电致蓝光器件发光效率和稳定性方面的独特之处，为其在有机平板显示器件中的应用奠定坚实基础。

热活化延迟荧光是一种利用热作用下三线态激子到单线态激子的反转来提高材料发光效率的新技术。本课题主要设计思路是利用具有不同电性能和能级结构的芳环取代膦氧单元、嗪、二苯甲酮、咔唑、芴和芳香环砜类衍生物等作为主要桥联基团，合成一系列具有分子内电荷转移特征的可溶液加工型自掺杂热活化延迟荧光蓝色发光体。详细研究热活化延迟荧光蓝色发光体的合成路线、探索温度和反应物配比等反应条件对产物纯度和产率的影响。研究桥联基团的种类、取代位置以及分子拓扑结构的多样化对材料的能级、共轭长度、热稳定性和光物理性质的影响，进而独立调节其热稳定性、载流子迁移率和能级结构等指标参数，得到具有自搀杂特征的可溶液加工型热活化延迟荧光蓝色发光体，实现其电致发光器件的外量子效率大于10%，系统研究可溶液加工、自掺杂和热活化延迟荧光三重策略在提高电致蓝光器件效率和稳定性方面的独特之处。2005年以来，我们紧扣主题、科学施策，具体从芴类热活化延迟蓝光材料、具有聚集诱导荧光增强和热活化延迟荧光双重特性电致蓝光材料和基于嘧啶、吡嗪和咔唑的同分异构高性能热活化延迟蓝光材料的光电性质的差异性等角度出发，开展了卓有成效的研究工作，部分宽能隙发光材料电致发光器件的最大外量子效率超过5%。此外，我们得到了一系列基于咔唑衍生物、二苯甲酮和2,4,6-三苯基-1,3,5-三嗪的有机多功能发光材料，从改变其取代模式和凝聚态结构两个角度实现室温磷光和热活化延迟荧光之间的转化，深化了对具有分子内电荷转移特征发光体的激发态性质的认识。截至现在，在项目资助下课题负责人以第一作者或者通讯作者身份在Polymer Chemistry，Organic Electronics， New Journal of Chemistry，Synthetic Metals，Chinese Journal of Polymer Science，Chinese Journal of Organic Chemistry和应用化学等期刊上发表高质量研究论文11篇，其中SCI收录论文9篇，申请中国发明专利4项，完成江苏省高校自然科学研究面上项目1项，培养博士研究生3人，硕士研究生8人。未来我将继续努力，多角度深化对前期所合成材料光电性质的表征和总结，争取取得更加丰硕的科研成果。