分子折叠增强自旋轨道耦合诱导高效率纯有机室温磷光

To develop high-efficiency, pure organic (metal-free) room-temperature phosphorescence (RTP) materials is a very challenging subject. Based on the study of excited state, the structure-property relationship is disclosed among molecular folding, excited state characteristics, phosphorescence properties, and the new mechanism is put forward to greatly strengthen the spin orbit coupling for pure organic metal-free molecular systems. With the combination of theory and experiment, the systematical investigations are carried out, including the formation of folding structure in different molecular units and the modulation of excited state properties. The effects of molecular folding structure factors (e.g., heteroatom species, folding number, folding, folding position, substituent, etc.), environmental factors (e.g., solvent polarity, stacking mode, supramolecular interaction, viscosity and rigidity of matrix, etc.) are well clarified on the excited state properties (e.g., order of energy levels, electron transition characteristics, spin orbit coupling, efficiency and lifetime, single-triplet energy splitting ΔEST, etc.). Excited state dynamics is studied to elucidate the essence of photophysical and photochemical process, aiming to develop high-efficiency, pure organic room-temperature phosphorescence materials with novel structures and new systems, and to expand new principles and novel applications for pure organic room-temperature phosphorescence. Finally, we try to achieve the independent intellectual property rights in a new-generation high-efficiency, low cost, pure organic (metal-free) room-temperature phosphorescence materials in terms of designs, principles and applications.

发展高效率、纯有机（不含金属）室温磷光材料是一个充满挑战性的课题。申请者从激发态研究入手，围绕分子折叠、激发态特征、磷光性能主线，开展结构与性质关系研究，探索纯有机（不含金属）分子体系中增强自旋轨道耦合的新机理。理论与实验结合，系统研究不同分子基元折叠结构的形成和激发态性质的调控，揭示分子折叠结构因素（如杂原子种类、折叠程度、折叠数目、折叠位置、取代基等）、环境因素（溶剂极性、堆积方式、超分子作用强度、基质黏度和刚性等）影响激发态性质（能级顺序、电子跃迁特征、自旋轨道耦合、系间窜越、效率、寿命、单三重态能级劈裂ΔEST等）的内在规律。开展激发态动力学研究，探讨光物理与光化学过程的本质，发展高效率、纯有机室温磷光材料的新结构与新体系，拓展纯有机室温磷光的新原理与新应用，争取新一代高效率、低成本、纯有机室温磷光材料方面的自主知识产权。

开发高效率纯有机（不含重金属原子）室温磷光材料是一个充满挑战性的研究方向，不仅能够解决纯有机电致发光材料中75%三重态激子利用的关键科学问题，而且可以实现新一代有机电致发光材料的自主知识产权。项目以激发态研究为主线，系统研究了分子内折叠结构的设计与构筑、激发态性质调控，以及分子折叠结构影响室温磷光性质（三重态激子形成和磷光发射）的本质机理与客观规律。重点围绕具有分子内折叠结构的噻蒽及其衍生物，展开结构与性质关系研究，发现了噻蒽是一个具有高效率纯有机室温磷光发射的特征单元，深入揭示了噻蒽进行高效率室温磷光发射的内在本质机理，提出了分子折叠增强自旋-轨道耦合，诱导高效率纯有机室温磷光发射的新机制；进一步，以折叠分子噻蒽为核心单元，优化噻蒽衍生物的结构设计，提升室温磷光材料发光性能，验证了分子折叠增强纯有机室温磷光发射的机理，获得了几种高性能纯有机室温磷光材料（最高室温磷光效率为75%）；努力拓展了纯有机室温磷光材料的新应用，如在荧光-磷光双色白光照明、高灵敏氧气传感与检测（KSV=13.32 KPa-1，猝灭效率高达98.4%）、刺激响应等领域表现出独特的应用前景。总之，项目发现了增强纯有机室温磷光的新机制，发展了纯有机室温磷光材料新体系，拓展了纯有机室温磷光的新应用，在新一代高效率、低成本、纯有机室温磷光材料方面具有自主知识产权。项目执行期间，在CCS Chemistry, J. Phys. Chem. Lett., Adv. Optical. Mater.等杂志共发表SCI标注论文8篇，受到国内外同行的广泛关注和积极评价引用，项目申请中国发明专利3项，其中2项专利获得授权。