Enhancement of the Performance of Dye-Sensitized Solar Cell by Formation of Shallow Transport Levels under Visible Light Illumination

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• 作者：Qing Wang ; Zhipan Zhang ; Shaik M. Zakeeruddin ; Michael Grä ; tzel
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：May 1, 2008
• 年：2008
• 卷：112
• 期：17
• 页码：7084 - 7092
• 全文大小：268K
• 年卷期：v.112,no.17(May 1, 2008)
• ISSN：1932-7455

文摘

The performance enhancement of dye-sensitized solar cells (DSCs) in lithium-free and lithium-containingelectrolytes under visible light-soaking was examined by impedance spectroscopy and photovoltage transientdecay measurements. The improvement was found to arise from the formation of electronic transport levelsclose to the conduction band, resulting most likely from photoinduced proton intercalation in the TiO₂nanoparticles. These shallow trapping states accelerate the charge carrier transport within the nanocrystallinefilms without deteriorating the open circuit photovoltage. Subjecting the cells to forward bias in the darkproduces a similar effect, whereas the introduction of lithium ions in the electrolyte suppresses the phenomenadue to prevailing lithium ion intercalation. The redistribution of localized states in the band gap of TiO₂ andthe resulting conduction band edge movement appears to play a significant role in the performance of theDSC.