Unraveling the Nonideal Recombination Kinetics in Cobalt Complex Based Dye Sensitized Solar Cells: Impacts of Electron Lifetime and the Distribution of Electron Density
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- 作者：Yudan Wang ; Zhe Sun ; Hui Wang ; Mao Liang ; Song Xue
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：July 7, 2016
- 年：2016
- 卷：120
- 期：26
- 页码：13891-13900
- 全文大小：491K
- 年卷期：0
- ISSN：1932-7455
文摘
Kinetics of the recombination at TiO2/dye/electrolyte interfaces is vital to establish reliable strategy for reducing energy loss in dye sensitized solar cell (DSCs). The semilogarithmic plots of open circuit voltage–light intensity indicate that the DSCs exhibit different recombination behaviors in high and low voltage regions. Even so, the average orders of recombination reaction in the two regions are both found to be expressed as the summation of the apparent charge transfer coefficient and the averaged density distribution parameter. This statement is based upon the fact that the “steady-state” electron lifetimes in cobalt complex based DSCs are well interpreted by using the Butler–Volmer model. Combining the results of electron lifetime, the order of recombination reaction, and density distribution, we addressed that the dominant pathway of recombination in cobalt complex based DSCs is via the trapping states rather than the conduction band. In addition, the variation of the Fermi level in TiO2 film could affect the adsorbing configurations of 4-tert-butylpyridine molecules and Li+/H+ cations at TiO2 surfaces and hence engenders the nonexponential distribution of electron density at higher Fermi level.