Experimental Investigation of Back Electron Transfer and Band Edge Shift in Dyed TiO2 Electrodes

详细信息    查看全文

• 作者：Changneng Zhang ; Shuanghong Chen ; Huajun Tian ; Yang Huang ; Zhipeng Huo ; Songyuan Dai ; Fantai Kong ; Yifeng Sui
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：May 5, 2011
• 年：2011
• 卷：115
• 期：17
• 页码：8653-8657
• 全文大小：814K
• 年卷期：v.115,no.17(May 5, 2011)
• ISSN：1932-7455

文摘

In this work, we investigated the iodine effect on the kinetics of back electron transfer and the band edge shift in the dyed TiO₂ semiconductor electrodes. The iodine adsorbed on the TiO₂ surface as the recombination centers resulted in the positive shift in band edge of the TiO₂ electrode with the increase of I₃^{鈭?/sup> concentration. Detailed analysis of the back electron transfer indicated that the higher value of the transfer coefficient under the irradiation condition than in the dark was due to the possible faster recombination channels about the decomposition of I₂ and the decomposition of I₂ via the triplet-state sensitizers on the TiO₂ surface. From impedance spectra of the solar cells, it could be concluded that the smaller charge transfer resistance at the TiO₂/electrolyte interface was attributed to the positive shift of band edge in the iodine-adsorbed TiO₂ electrode with the increase of I₃鈭?/sup> concentration in the electrolytes. An analytical dependence of the short-circuit photocurrent density (J_sc) on the illumination intensity found that the increased efficiency of electron injection (桅_inj) could be attributed to the positive shift of band edge in the iodine-adsorbed TiO₂ electrode, resulting in a slightly increased J_sc.}