利用吸热延迟荧光机制的高效蓝光荧光OLED材料与器件

Blue Organic Light Emitting Diodes (OLED) have become the bottleneck of the white OLEDs in solid-state lighting applications, for they can't achieve high efficiency and good stability simultaneously. The novel fluorescent OLED based on thermally activated delayed fluorescence (TADF) supplies a new pathway to solve such bottleneck, because such TADF based blue fluorescent OLEDs not only could utilize the triplet excitons by a thermal up-conversion to achieve 100% internal quantum efficiency, but also replace the unstable blue phosphors by blue fluorophors. However, the design strategies of the new blue fluorophors and the device structures are still unclear. Therefore, in this research project, after carefully analyzing the mechanism of such novel TADF based fluorescent OLED, we aim to achieve high performance blue OLEDs by detailedly investigating: 1) the relationship between fluorescent quantum yield, singlet-triplet splitting and the chemical structure of the molecule, 2) new highly efficient blue fluorophors, and 3) The device structures of highly efficient TADF based blue fluorescent OLEDs. The achievements on this project will not only increase the known on how to design the organic optoelectronic materials, but also solve the bottleneck of the WOLEDs in solid-state lighting applications.

蓝光有机电致发光器件 (OLED) 由于不能实现效率与寿命的兼顾，近年来已经成为白光OLED技术在固体照明领域应用的最大瓶颈。利用吸热延迟荧光机制的新型荧光OLED技术，不但能够通过吸热上转换利用三重态激子，实现100%内量子效率，同时还可以避免使用不稳定的蓝光磷光材料，为解决这一瓶颈问题提供了理想方案，然而吸热延迟荧光蓝光OLED的研究目前尚处于起步阶段，新型蓝光荧光材料的分子设计规律、器件结构方案等尚不清楚。本项目将通过对吸热延迟荧光OLED技术内在发光机制的分析，以及对新型蓝光荧光材料需具备特性的理解，并将通过研究1）材料荧光量子产率和电子交换能与分子结构的关系；2）新型高效蓝光荧光材料的设计与合成；3）高效吸热延迟荧光蓝光OLED器件结构；获得高性能的蓝光OLED器件。项目的研究将为调控有机分子材料光电子性质，解决蓝光OLED瓶颈问题以及促进OLED技术的发展提供理论和实验基础。

蓝光有机电致发光器件(OLED)由于不能实现效率与寿命的兼顾，近年来已经成为白光OLED 技术在固体照明领域应用的最大瓶颈。利用吸热延迟荧光机制的新型荧光OLED技术，不但能够通过吸热上转换利用三重态激子，实现100%内量子效率，同时还可以避免使用不稳定的蓝光磷光材料，为解决这一瓶颈问题提供了理想方案。本项目针对新型TADF蓝光OLED技术中三个核心问题，通过研究分子结构与材料关键性质之间的关系，高效TADF蓝光荧光材料的体系的设计与合成，基于新型蓝色荧光材料的高效OLED器件，成功建立了具有电荷转移跃迁特征的新型TADF蓝光荧光材料的关键构效关系，发展了多个新型单分子TADF蓝光荧光材料体系以及激基复合物发光体系，基于新型蓝光荧光材料的蓝光OLED与白光OLED器件效率达到了目前已报道的同类OLED器件效率的最佳水平。本项目相关研究工作培养博士研究生3名与硕士研究生2名，发表了具有较高学术价值的SCI研究论文23篇，申请国内发明专利10项，超额完全了预期成果。本项目的成果也将为调控有机分子材料光电子性质，解决蓝光OLED瓶颈问题以及促进OLED技术的发展提供理论和实验基础。