Effects of bridging ligands on the current-potential behavior and interfacial kinetics of ruthenium-sensitized nanocrystalline TiO2 photoelectrodes
Effects of bridging ligands on the current-potential behavior and interfacial kinetics of ruthenium-sensitized nanocrystalline TiO2 photoelectrodes
复制标题
桥联配体对钌敏化纳米晶TiO2光电极电流-电位行为和界面动力学的影响
DOI：
10.1021/jp021921u
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发表时间：
2003
影响因子：
2.9
通讯作者：
H. Gray
中科院分区：
文献类型：
--
作者：
K. Kilså;E. I. Mayo;D. Kuciauskas;R. Villahermosa;N. Lewis;J. Winkler;H. Gray
我们发现Ru^（II）（bpy）_2（bpy-4-（xylyl）_x-邻苯基-COOH）（PF_6）_2（简称Rux，其中x = 0，1或2个二甲苯基; bpy = 2，2 '-bipyridine）染料在模拟太阳光照射下可以作为纳米TiO_2的敏化剂，但效率较低。短路光电流密度和开路电压均随x的增大而减小。x = 0染料的电子注入（10^6−10^8 s^（-1））稍快，但x = 2染料的复合（10^（-15）−10^（-13）cm^3 s^（-1））和再生（10 mM I^-为10^4−10^6 s^（-1））稍快。我们认为，距离依赖性的缺乏是由于灵活的一个羧基连接到表面，导致Ru−TiO_2的电子隧穿距离非常相似的x = 0，1和2。对于所有的Rux敏化剂，在黑暗中产生电流所需的电位都相对较小，这表明Rux敏化剂和未修饰的TiO_2电极一样有利于TiO_2和I_3^-/I^-电解质溶液中电子之间的反应。
We have shown that Ru^(II)(bpy)_2(bpy-4-(xylyl)_x-≡-phenyl-COOH)(PF_6)_2 (abbreviated Rux, where x = 0, 1 or 2 xylyl groups; bpy = 2,2‘-bipyridine) dyes can act as sensitizers for nanocrystalline TiO_2 in functional photoelectrochemical cells under simulated solar illumination, albeit with low efficiencies. Both the short-circuit photocurrent density and the open-circuit voltage decreased as x was increased. Electron injection (10^6−10^8 s^(-1)) was slightly faster for the x = 0 dye, but both recombination (10^(-15)−10^(-13) cm^3 s^(-1)) and regeneration (10^4−10^6 s^(-1) for 10 mM I^-) were slightly faster for the x = 2 dye. We suggest that the lack of distance dependence is due to the flexible one-carboxyl attachment to the surface resulting in the Ru−TiO_2 electron-tunneling distance being very similar for x = 0, 1, and 2. For all of the Rux sensitizers, a relatively small potential was needed for generation of current in the dark, indicating that the reaction between electrons in TiO_2 and the I_3^-/I^- electrolyte solution is as favorable for the Rux sensitizers as for unmodified TiO_2 electrodes.