具有给体-受体间弱相互作用的新型延迟荧光材料的设计合成及性能研究

Thermally activated delayed fluorescent (TADF) materials, which can harvest both triplet (T1) and singlet (S1) excitons for electroluminescent via efficient reverse intersystem crossing, have emerged as promising fluorescent dyes for the construction of efficient OLEDs. Utilization of TADF emitters provides an opportunity not only to reduce the overreliance on expensive precious metals for efficient OLEDs, but also to solve the urgent issue of developing stable and efficient blue materials and their devices. Based on our preliminary results, herein, we propose to design and synthesize a type of TADF molecules with significant intramolecular Donor–Acceptor (D-A) interactions, in which charge is transferred not only through chemical bonds but also through space mediated by the intramolecular D-A interactions. Besides, the strong intramolecular interactions could effectively suppress intramolecular vibration relaxation which accelerates radiationless decay. In this proposal, on the one hand, we will develop a new family of efficient TADF materials with small ∆EST, and develop highly efficient OLEDs based on these materials. On the other hand, a systematical study on the chemical structure, electronic structure, photophysical properties, stabilities and electroluminescence properties of these materials will deepen the understanding of the relationship between structures and properties, and thus provide valuable reference for Design & Synthesis of TADF materials.

热活化延迟荧光(TADF)材料能够充分利用电激发形成的单重态激子和三重态激子发光，是一类高效的有机电致发光材料。对TADF材料的研究有望突破贵金属磷光材料的专利壁垒和蓝光器件的技术瓶颈。通过综合分析现有TADF材料的特点及TADF分子设计的难点，本项目在前期研究的基础上提出设计合成一类电子给体和电子受体间具有较强分子内弱相互作用的TADF分子，使其给体-受体间电荷转移能同时通过化学键和分子内弱相互作用进行。同时，较强的分子内弱相互作用能有效抑制非辐射跃迁。本项目的设立与开展，一方面有望解决TADF分子设计时∆EST和发光效率难以兼顾的问题，并丰富TADF材料的研究体系，获得高效的新型TADF材料及其器件。另一方面，通过系统研究该类材料的分子结构、电子结构、光物理性能、稳定性能和电致发光性能等，获得对其结构-性能间联系的深层次认识，为TADF材料的设计合成提供理论和经验指导。

热活化延迟荧光（TADF）是一类高效有机电致发光材料，有望替代贵金属磷光材料构筑高性能有机发光二极管（OLED）器件，在照明和显示领域有广阔的应用前景。针对TADF材料的特点及其分子设计的难点，本项目从TADF材料构效关系调控出发，主要围绕提高材料的发光效率、降低发光寿命、调节发光波长及优化成膜性能等，设计合成了系列高性能的新型TADF分子，并制备了基于该类材料的高效OLED器件。TADF材料薄膜态光致发光效率超过90%，延迟荧光寿命低至1.4μs，并具有优异的稳定性能和成膜性能。OLED器件外量子效率EQE最高超过25%。通过对该类材料的分子结构与堆积方式（特别是分子内及分子间弱相互作用）、电子结构、光物理性质、稳定性能和电致发光性能的系统研究，获得了对其结构-性能间关系的深层次认识，为TADF材料的设计合成提供理论和经验指导。本项目取得了系列具有自主知识产权的研究成果，共发表有该基金资助号的SCI研究论文10篇，其中，中科院大类一区期刊论文5篇（影响因子均大于9），中科院大类二区期刊论文4篇。申请发明专利4项。培养了4名博士，1名硕士。