Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), JST CREST, Kyushu University , 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
J Am Chem Soc. 2013 Dec 26;135(51):19056-9. doi: 10.1021/ja411316s. Epub 2013 Dec 12.
A nonvolatile, in-air functioning liquid photon upconverting system is developed. A rationally designed triplet sensitizer (branched alkyl chain-modified Pt(II) porphyrin) is homogeneously doped in energy-harvesting liquid acceptors with a 9,10-diphenylanthracene unit. A significantly high upconversion quantum yield of ∼28% is achieved in the solvent-free liquid state, even under aerated conditions. The liquid upconversion system shows a sequence of efficient triplet energy transfer and migration of two itinerant excited states which eventually collide with each other to produce a singlet excited state of the acceptor. The observed insusceptibility of upconversion luminescence to oxygen indicates the sealing ability of molten alkyl chains introduced to liquefy chromophores. The involvement of the energy migration process in triplet-triplet annihilation (TTA) provides a new perspective in designing advanced photon upconversion systems.
开发了一种非易失性、在空气中工作的液体上转换系统。一种经过合理设计的三重态敏化剂（支化烷基链修饰的 Pt(II) 卟啉）均匀掺杂在能量收集液体受体中，其中包含 9,10-二苯基蒽单元。即使在有氧条件下，在无溶剂的液体状态下也可实现高达 28%的上转换量子产率。该液体上转换系统表现出一系列有效的三重态能量转移和两个巡游激发态的迁移，最终它们相互碰撞产生受体的单重激发态。观察到上转换发光对氧气的不敏感性表明引入液化生色团的熔融烷基链的密封能力。能量迁移过程在三重态-三重态湮灭（TTA）中的参与为设计先进的光子上转换系统提供了新的视角。
