Photoinduced ultrafast dynamics of coumarin 343 sensitized p-type-nanostructured NiO films
Photoinduced ultrafast dynamics of coumarin 343 sensitized p-type-nanostructured NiO films
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DOI：
10.1021/jp053230e
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发表时间：
2005-10-20
影响因子：
3.3
通讯作者：
Hammarström, L
中科院分区：
文献类型：
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作者：
Morandeira, A;Boschloo, G;Hammarström, L
通过飞秒瞬态吸收光谱探测白光，测量了光诱导电子从纳米晶 NiO（一种 p 型半导体）的价带转移到受激结合染料香豆素 343 以及随后的复合。发现这两个过程都是非指数过程。从半导体到激发态结合染料的光致电子转移具有超快分量（类似于 200 fs），与 C343-TiO2 胶体溶液中光致电子注入测量的时间常数相当。该过程非常有效，是激发染料失活的主要途径。反向电子转移也非常快，复合过程的主要部分发生的时间常数约为 20 ps。染料敏化纳米结构p型半导体是有吸引力的材料，因为它们具有作为染料敏化太阳能电池中的光电阴极和固态染料敏化太阳能电池中的固体电解质的潜在用途。据我们所知，这是首次研究敏化p型半导体的光致电子转移动力学。
Photoinduced electron transfer from the valence band of nanocrystalline NiO, a p-type semiconductor, to an excited bound dye, coumarin 343, and the subsequent recombination have been measured by femtosecond transient absorbance spectroscopy probing with white light. It was found that both processes are nonexponential. The photoinduced electron transfer from the semiconductor to the excited bound dye has an ultrafast component (similar to 200 fs), which is comparable to the time constants measured for photoinduced electron injection in C343-TiO2 colloid solutions. The process is very efficient and constitutes the main path of deactivation of the excited dye. Back electron transfer is also remarkably fast, with the main part of the recombination process happening with a time constant of similar to 20 ps. Dye-sensitized nanostructured p-type semiconductors are attractive materials due to their potential use as photocathodes in dye-sensitized solar cells and solid electrolytes in solid-state dye-sensitized solar cells. To our knowledge, this is the first time that the photoinduced electron-transfer kinetics of a sensitized p-type semiconductor has been studied.