三重态-三重态湮灭上转换(TTA-UC)是实现光子上转换的方法之一，因其可使用低能量密度非相干光源作为激发光源，近年来已成为上转换研究前沿。芳醚树枝形聚合物具有多末端基和构象折叠的结构特点，聚集诱导发光(AIE)化合物在聚集态具有高的发光量子产率，本项目拟结合芳醚树枝形聚合物结构优势和AIE发色团的特点，拟选择AIE基团作为受体湮灭剂，将受体湮灭剂修饰至树枝形聚合物外围，构筑共价/非共价高效TTA-UC体系。研究TTA-UC体系光敏剂与受体湮灭剂间三重态能量传递过程和受体三重态-三重态湮灭过程，测定体系上转换发光量子产率；揭示树枝形聚合物结构对TTA-UC体系光物理过程的影响，以及具有AIE性质受体基团的应用对TTA-UC发光效率的促进作用；探索基于树枝形聚合物结构的TTA-UC体系在细胞成像中的应用。本项目将为构筑高效TTA-UC体系提供重要的理论和实验依据。

Triplet-triplet annihilation upconversion (TTA-UC) is one of the techniques to achieve photon upconversion, which can take place upon excitation with low-intensity and noncoherent light source. Many efforts have been devoted to the development of TTA-UC systems with high efficiency. Poly(aryl ether) dendrimers are regularly and hierarchically branched macromolecules with numerous chain ends and folded conformation. Aggregation-induced emission (AIE) chromophores have higher emission quantum yield at aggregate states. In this project, we attempt to take advantages of the specific structure of poly(aryl ether) dendrimers and the characteristics of AIE chromophores to construct a series of novel, efficient covalent/noncovalent-TTA-UC systems in liquid/solid states. The AIE chromophores attaching to the periphery of poly(aryl ether) dendrimers and the palladium porphyrin derivatives are selected as the acceptor annihilator and the triplet photosensitizer, respectively. The photophysical processes of the TTA-UC systems, including the triplet-triplet energy transfer between the photosensitizer and the acceptor annihilator and the triplet-triplet annihilation among the annihilator will be investigated, and the upconversion quantum efficiency will also be measured. The effect of dendritic frameworks and AIE chromophores on the upconversion quantum efficiency will be discussed. The application of the TTA-UC system based on dendritic structure in bioimaging will be explored. This work will provide a new strategy for developing efficient TTA-UC systems.