摘要/Abstract
三重态-三重态湮灭（TTA）上转换是一项将低能量的光转换成高能量光的技术，具有所需激发光强度低、光敏剂吸光能力强、工作波长可调、量子效率高等优点，因其在太阳能电池、生物成像、光催化及光电器件等方面的潜在应用价值而受到广泛关注.由于TTA上转换的两个重要过程——三重态光敏剂向受体的能量传递（TTET）与受体分子间发生三重态湮灭（TTA）均属于Dexter机制，需要通过碰撞来完成，因而目前TTA上转换多数在低粘度、除氧的有机溶剂中完成，这在一定程度上限制了它的实际应用.近年来，探索能够隔绝空气、分子扩散受限体系中特别是固相中的高效上转换受到研究者的广泛关注.介绍了TTA上转换发光机理，详细综述了TTA上转换在包括高分子聚合物、固态晶体、超分子凝胶、超分子自组装体以及纳米颗粒等聚集体中的研究进展.
关键词: 聚集体, 三重态-三重态湮灭, 能量上转换
Triplet-triplet annihilation (TTA) upconversion, a unique technique that converting low-energy photons into higher-energy photons, has attracted much attention owing to its potential applications in various fields, such as solar cells, bioimaging, photocatalysis and photoelectric device. TTA upconversion has several advantages over other upconversion methods, such as allowing for the use of low excitation power density, readily tunable excitation/emission wavelength and high upconversion quantum yield. Both triplet-triplet energy transfer (TTET) and TTA processes in TTA upconversion follow the Dexter energy transfer mechanism. The components involved have to diffuse in the media and collide within the lifetime of their excited states to complete the energy transfer. Thus, most efficient TTA-based upconversion has been achieved with donor-acceptor pairs that are molecularly dissolved in deaerated organic solvents, which however significantly limited their practical applications. In recent years, more and more efforts have beendevoted to explore high-efficient TTA upconversion under aerated conditions by employing specific solid materials or viscous liquids as matrices to block oxygen. The recent advance of research of TTA upconversion in aggregated systems is summarized, including rubbery polymers, gels, molecular crystals, nanoparticles and supramolecular self-assemblies.
Key words: aggregation, triplet-triplet annihilation, energy upconversion
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