Ultrafast terahertz conductivity dynamics in mesoporous TiO2: Influence of dye sensitization and surface treatment in solid-state dye-sensitized solar cells
Ultrafast terahertz conductivity dynamics in mesoporous TiO2: Influence of dye sensitization and surface treatment in solid-state dye-sensitized solar cells
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DOI：
10.1021/jp908760r
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发表时间：
2010-01
影响因子：
3.7
通讯作者：
Priti Tiwana;P. Parkinson;M. Johnston;H. Snaith;L. Herz
中科院分区：
文献类型：
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作者：
Priti Tiwana;P. Parkinson;M. Johnston;H. Snaith;L. Herz
我们已经使用光泵太赫兹探测光谱，探讨光诱导的电导动力学介孔TiO 2薄膜，通常采用染料敏化太阳能电池的电子传输电极。我们发现一个固有的迁移率值为0.1 cm 2/（V s）和电子运动通过TiO 2矩阵的扩散长度为20 nm。二氧化钛薄膜的光电导动力学，无论是之前和之后敏化钌bypyridyl络合物称为Z907，进行了检查，以研究电荷注入，捕获，和复合时间尺度。我们观察到来自Z907的双相电荷注入，快速的亚500 fs分量，随后是较慢的70−200 ps分量。这是其次是光电导衰减在最初的几个纳秒，主要反映电荷载流子捕获。此外，我们还利用太赫兹光谱研究了用TiCl 4处理二氧化钛表面对早期电荷动力学的影响。在太阳能电池中，表面处理是一种非常重要的技术。
We have used optical-pump terahertz-probe spectroscopy to explore the photoinduced conductivity dynamics in mesoporous anatase TiO2 films, commonly employed as the electron-transporting electrode in dye-sensitized solar cells. We find an intrinsic mobility value of 0.1 cm2/(V s) and diffusion length of ∼20 nm for electron motion through the TiO2 matrix. The photoconductivity dynamics in TiO2 films, both before and after sensitization with a ruthenium bypyridyl complex termed Z907, were examined in order to study the charge injection, trapping, and recombination time scales. We observe a biphasic charge injection from Z907, with a fast sub-500 fs component, followed by a slower 70−200 ps component. This is followed by photoconductivity decay over the first few nanoseconds, predominantly reflecting charge carrier trapping. In addition, we have utilized terahertz spectroscopy to investigate the influence of treating the titania surface with TiCl4 on early-time charge dynamics. In the solar cells, surface tre...