Ai Xin, Anderson Neil A, Guo Jianchang, Lian Tianquan
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
J Phys Chem B. 2005 Apr 21;109(15):7088-94. doi: 10.1021/jp046037d.
Ultrafast infrared spectroscopy was utilized to investigate the electron-transfer dynamics from Ru(dcbpy)(2)(X)(2) complexes (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine; X(2) = SCN(-), 2CN(-), and dcbpy; referenced as RuN3, Ru505, and Ru470, respectively) to nanocrystalline SnO(2) films. For both films exposed to air (dry) and submerged in a pH 2 buffer solution, all traces show biphasic dynamics with a small ultrafast component (less than 10%) and nonexponential slow component, indicating that most injection occurs from thermalized excited state of the dye. In the dry film, the injection rate becomes slower, comparing RuN3, Ru505, and Ru470, correlating with decreasing excited-state oxidation potentials in these dyes. However, the variation of injection rate with dye potential is less noticeable at pH 2. The possible reason for the different injection dynamics in these dyes and under different environments are discussed. These injection dynamics are also compared with those on TiO(2) and ZnO.
利用超快红外光谱研究了从Ru(dcbpy)(2)(X)(2)配合物（dcbpy = 4,4'-二羧基-2,2'-联吡啶；X(2) = SCN(-)、2CN(-)和dcbpy；分别称为RuN3、Ru505和Ru470）到纳米晶SnO(2)薄膜的电子转移动力学。对于暴露在空气中（干燥）和浸没在pH 2缓冲溶液中的两种薄膜，所有曲线均显示出双相动力学，具有一个小的超快成分（小于10%）和非指数形式的慢成分，这表明大多数注入发生在染料的热激发态。在干燥薄膜中，比较RuN3、Ru505和Ru470时，注入速率变得更慢，这与这些染料中激发态氧化电位的降低相关。然而，在pH 2时，注入速率随染料电位的变化不太明显。讨论了这些染料在不同环境下不同注入动力学的可能原因。还将这些注入动力学与在TiO(2)和ZnO上的动力学进行了比较。
