XPS, UV鈥揤is, FTIR, and EXAFS Studies to Investigate the Binding Mechanism of N719 Dye onto Oxalic Acid Treated TiO2 and Its Implication on Photovoltaic Properties

详细信息    查看全文

• 作者：Jaspreet Singh ; Abhay Gusain ; Vibha Saxena ; A.K. Chauhan ; P. Veerender ; S. P. Koiry ; P. Jha ; Avani Jain ; D.K. Aswal ; S. K. Gupta
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 17, 2013
• 年：2013
• 卷：117
• 期：41
• 页码：21096-21104
• 全文大小：485K
• 年卷期：v.117,no.41(October 17, 2013)
• ISSN：1932-7455

文摘

The anchoring mechanism of N719 dye molecules on oxalic acid treated TiO₂ (OA-TiO₂) electrodes has been investigated using extended X-ray absorption fine structure (EXAFS) measurements, Fourier transform infrared spectroscopy (FTIR), UV鈥搗is spectroscopy, and X-ray photoelectron spectroscopy (XPS). The FTIR spectroscopy of OA-TiO₂ electrodes revealed that the oxalic acid dissociates at the TiO₂ surface and binds through bidentate chelating and/or bidentate bridging. Analyses of EXAFS, FTIR, UV鈥搗is, and XPS measurements of N719 dye loaded onto OA-TiO₂ revealed that the binding of N719 molecules takes place via interaction between the Ru atom of the dye and O^{鈥?/sup> of bidentate bridged oxalate ions at the TiO₂ surface. This mechanism is quite different from the binding of N719 onto untreated TiO₂ (WO-TiO₂) surface, where 鈭扖OOH and SCN groups of the dye directly bind to the TiO₂ surface. The analyses of UV鈥搗is data show that the amount of N719 dye loading onto OA-TiO₂ surface is much higher than that onto the native TiO₂ surface. In addition, the incident photon-to-current conversion efficiency (IPCE) measurements show that the presence of oxalate ions between the dye and TiO₂ surface favors efficient electron transfer and therefore improvement in device efficiency. The dye-sensitized solar cells fabricated using N719 dye sensitized onto OA-TiO₂ showed an efficiency of 4.6%, which is significantly higher than that based on a WO-TiO₂ electrode (3.2%).}