Nishikiori Hiromasa, Takeshita Masahiro, Komatsu Yoshihiro, Satozono Hiroshi, Teshima Katsuya
Department of Materials Chemistry, Graduate School of Science and Technology, Department of Environmental Science and Technology, Faculty of Engineering, and Center for Energy and Environmental Science, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan.
Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamamatsu 434-8601, Shizuoka, Japan.
ACS Omega. 2018 Aug 1;3(8):8529-8536. doi: 10.1021/acsomega.8b01107. eCollection 2018 Aug 31.
Photon upconverted emission based on dye-sensitized triplet-triplet annihilation was observed in silica gel systems containing Pt(II) octaethylporphyrin (triplet sensitizer) and 9,10-diphenylanthracene (singlet emitter). The triplet sensitizer was encapsulated and highly dispersed in the silica gels prepared by the sol-gel method. The singlet emitter was adsorbed on the silica gel pores accessible to the outside. Phosphorescence of the triplet sensitizer was partially quenched, and the singlet emission was enhanced with an increase in the concentration of the singlet emitter. The emission intensity increased in proportion to the approximate square of the irradiation power. The triplet energy transfer from some of the encapsulated triplet sensitizer molecules to the adsorbed singlet emitter molecules was observed in the silica gels followed by the triplet-triplet annihilation and upconverted singlet emission. The phosphorescence quenching and upconverted singlet emission were more significantly observed in the gel dried at a lower temperature (wetter gel). The wetter gel contained higher amounts of solvent and water molecules, in which the triplet sensitizer and singlet emitter should collide and then the sensitized emitters should collide between themselves during their excited-state lifetime. The photon upconversion process required the triplet sensitizer and singlet emitter molecules to be in an environment similar to the solvents.
在含有铂（II）八乙基卟啉（三重态敏化剂）和9,10 - 二苯基蒽（单重态发射体）的硅胶体系中观察到了基于染料敏化三重态 - 三重态湮灭的光子上转换发射。三重态敏化剂被封装并高度分散在通过溶胶 - 凝胶法制备的硅胶中。单重态发射体吸附在硅胶可通向外部的孔隙上。三重态敏化剂的磷光被部分猝灭，并且随着单重态发射体浓度的增加单重态发射增强。发射强度与照射功率的近似平方成正比。在硅胶中观察到了从一些被封装的三重态敏化剂分子到吸附的单重态发射体分子的三重态能量转移，随后发生三重态 - 三重态湮灭和上转换单重态发射。在较低温度下干燥的凝胶（更湿的凝胶）中更显著地观察到磷光猝灭和上转换单重态发射。更湿的凝胶含有更高量的溶剂和水分子，在其中三重态敏化剂和单重态发射体应该发生碰撞，然后敏化发射体在其激发态寿命期间应该相互碰撞。光子上转换过程要求三重态敏化剂和单重态发射体分子处于类似于溶剂的环境中。
