Dye-sensitized solar cells based on oriented TiO2 nanotube arrays:: Transport, trapping, and transfer of electrons
Dye-sensitized solar cells based on oriented TiO2 nanotube arrays:: Transport, trapping, and transfer of electrons
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DOI：
10.1021/ja804852z
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发表时间：
2008-10-08
影响因子：
15
通讯作者：
Walker, Alison B.
中科院分区：
文献类型：
--
作者：
Jennings, James R.;Ghicov, Andrei;Walker, Alison B.
染料敏化太阳能电池制造使用有序阵列的二氧化钛纳米管（管长5，10，和20 μ m）生长在钛已被其特征在于由一系列的实验方法。在短路条件下，即使对于20 μ m厚的纳米管阵列，电池中光注入电子的收集效率也接近100%。通过一系列互补的实验技术，详细研究了纳米管电池中电子的传输、捕获和反向转移。实验结果的分析表明，电子扩散长度（这取决于光注入的电子的扩散系数和寿命）是在二氧化钛纳米管电池的100 μ m的顺序。这与电子收集效率接近100%的观察结果一致，即使是研究中使用的最厚（20 μ m）的纳米管膜。该研究揭示了使用电荷提取技术实验测量的电子陷阱分布的形状与从瞬态电流和电压测量间接推断的形状之间的实质性差异。通过引入一个数值因子来解释纳米二氧化钛中自由电子的非理想热力学行为，解决了这种差异。
Dye-sensitized solar cells fabricated using ordered arrays of titania nanotubes (tube lengths 5, 10, and 20 mu m) grown on titanium have been characterized by a range of experimental methods. The collection efficiency for photoinjected electrons in the cells is close to 100% under short circuit conditions, even for a 20 mu m thick nanotube array. Transport, trapping, and back transfer of electrons in the nanotube cells have been studied in detail by a range of complementary experimental techniques. Analysis of the experimental results has shown that the electron diffusion length (which depends on the diffusion coefficient and lifetime of the photoinjected electrons) is of the order of 100 mu m in the titania nanotube cells. This is consistent with the observation that the collection efficiency for electrons is close to 100%, even for the thickest (20 mu m) nanotube films used in the study. The Study revealed a substantial discrepancy between the shapes of the electron trap distributions measured experimentally using charge extraction techniques and those inferred indirectly from transient current and voltage measurements. The discrepancy is resolved by introduction of a numerical factor to account for non-ideal thermodynamic behavior of free electrons in the nanostructured titania.