Theoretical Modeling of Measured Photocurrent Dynamics in Dye-Sensitized Nanostructured TiO2 Solar Cells

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• 作者：Liangmin Zhang ; Robert Engelken ; Deliang Cui
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：1293-1297
• 全文大小：334K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

The general solutions describing the buildup and decay processes of photocurrent in dye-sensitized nanocrystalline TiO₂ thin film solar cells have been derived by solving the diffusion equations that include charge transport and recombination parameters of electron lifetime and diffusion coefficient. One analytical solution is obtained under the condition of steady light illumination that may be used to interpret the buildup process of photocurrent. The other solution is derived with the condition that the illumination light is turned off after the photocurrent reaches its steady value. The latter solution can be used to describe the recombination process of charge carriers in the thin films. The two solutions have also been used to simulate experimentally measured results to extract electron lifetime, diffusion coefficient, and diffusion length of electrons for the two conditions under different light intensities. The fitted results show that the lifetime and diffusion coefficient vary with light intensity in opposite senses and the diffusion length only slightly depends on light intensity. In the recombination process, the dark diffusion coefficient is independent of excitation light intensity. These theoretical results confirm the observations reported by other researchers.