Photovoltaic Performance of Dye-Sensitized Solar Cells Based on Al-Doped TiO<sub>2</sub> Thin Films

Abstract

Al-doped TiO2 thin films were synthesized by the hydrothermal method. To prepare a working electrode, a TiO2 or AlTiO2 slurry was coated onto a fluorine-doped tin oxide glass substrate by the doctor blade method and the coated substrate was sintered at 450 ° C. TiO2 and Al-doped TiO2 films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and tested by the dye-sensitized solar cell (DSSCs) system. The influences of Al-doping on TiO2 crystal form and the photovoltaic performance of DSSCs were investigated. X-ray photoelectron spectroscopy (XPS) data indicate that the doped Al ions exist in the form of Al , and these ions play a role as e or h + traps and reduce the e/h + pair recombination rate. The corresponding MottSchottky plot indicates that the Al-doped TiO2 photoanode shifts the flat band potential positively. The positive shift of the flat band potential improves the driving force of injected electrons from the LUMO of the [Article] doi: 10.3866/PKU.WHXB201112161 www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2012, 28 (3), 591-595 March Received: October 26, 2011; Revised: December 13, 2011; Published on Web: December 16, 2011. ∗Corresponding authors. ZHOU Yang, Email: Yzhou@bjtu.edu.cn; Tel: +86-10-51685554. LIN Yuan, Email: liuyuan@iccas.ac.cn; Tel: +86-10-82615031. The project was supported by the National Key Basic Research Program of China (973) (2006CB202605), National High-Tech Research and Development Program of China (863) (2007AA05Z439), and National Natural Science Foundation of China (20973183). 国家重点基础研究发展规划项目(973) (2006CB202605),国家高技术研究发展计划项目(863) (2007AA05Z439)及国家自然科学基金项目 (20973183)资助 C Editorial office of Acta Physico-Chimica Sinica 591 Acta Phys. -Chim. Sin. 2012 Vol.28 dye to the conduction band of TiO2. The Al-doped TiO2 thin film shows a photovoltaic efficiency of 6.48%, which is higher than that of the undoped TiO2 thin film (5.58%) and the short-circuit photocurrent density increases from 16.5 to 18.2 mA·cm-2.