方菁染料敏化二氧化钛超微粒的光化学行为

通过吸收光谱、荧光猝灭、单光子计数等手段研究了2-(4-乙胺-2-羟基苯基)-4-(4-乙胺-苯基)-方菁染料(SQ)在TiO2超微粒体系中的光化学行为。结果表明, SQ强烈吸附在TiO2胶粒表面, 表观吸附常数为2.275×10^3mol^-^1 . dm^3。SQ的荧光能被TiO2有效地猝灭,猝灭的效率达97%。根据物质的氧化还原电位、光谱特性及荧光寿命的变化提出光诱导电子界面转移的荧光猝灭机理, 电子转移的速率常数为1.97×10^8s^-^1。

Investigation of photochemical behavior of a squaraine dye photosensitizing titanium dioxide ultrafine particles

Photochemical behavior of 2-(4-ethylamino-2-hydroxyphenyl)-4-(4-ethylaminophenyl)-squaraine (SQ) in TiO2 system was probed by UV-vis, fluorescence quenching, and nanosecond time-correlated single-photon counting. There was strong interaction between SQ and TiO2 colloidal particles with an apparent association constant of 2.275×10^3mol^-^1 . dm^3 obtained by the fluorescence quenching data. The fluorescence emission of SQ dye could be quenched by TiO2 colloid with an efficiency of 97%. The mechanism of photoinduced interface electron transfer for the fluoorescence quenching was proposed upon the spectral characters, potential discrepancy and the variation of the fluorescence lifetime. The rate constant for the electron injection process was 1.97×10^8 s^-^1 determined from the measurements of fluorescence lifetimes.