Electron Transport and Recombination in Photoanode of Electrospun TiO2 Nanotubes for Dye-Sensitized Solar Cells

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• 作者：Xiaoxu Wang ; Guangfei He ; Hao Fong ; Zhengtao Zhu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：January 31, 2013
• 年：2013
• 卷：117
• 期：4
• 页码：1641-1646
• 全文大小：307K
• 年卷期：v.117,no.4(January 31, 2013)
• ISSN：1932-7455

文摘

The technique of coaxial electrospinning has been adopted to prepare the TiO₂ nanotubes with average inner diameter of 275 nm and wall thickness of 115 nm. The electrospun TiO₂ nanotubes possess the anatase type of crystalline structure, well-defined tubular morphology, and large aspect ratio. The dye-sensitized solar cell (DSSC) based on the TiO₂ nanotubes alone has an efficiency of 3.33% with open-circuit voltage (V_oc) of 800 mV, short-circuit current (J_sc) of 6.01 mA cm^鈥?, and fill factor (FF) of 68.5%. Intriguingly, the addition of 20 wt % TiO₂ nanoparticles in the TiO₂ nanotubes improves the DSSC efficiency significantly. The charge transport and recombination in the fabricated DSSCs are characterized by the dark current, photovoltage as a function of light intensity, and transient photovoltage and photocurrent measurements. The results indicate that electrospun TiO₂ nanotubes have large diffusion coefficient and slow recombination compared to the mesoporous film of TiO₂ nanoparticles. The enhanced electron transport properties of the TiO₂ nanotubes combined with the facile and scalable preparation technique of electrospinning suggest that the electrospun TiO₂ nanotubes could be promising as photoanode material for low-cost and high-efficiency DSSCs.