Effects of TiO2 Coating on WO3 Inverse Opal Photoelectrode for Dye-sensitized Solar Cells

Abstract

This study is based on Research and Education (R&E) project in science high school. In this study, we compared the photoelectrochemical properties of pure WO3 and TiO2 coated WO3 inverse opal film after the development of dye-sensitized solar cells (DSSCs). That is, above the SnO2 inverse opal (IO), thin WO3 film was prepared by the facile electrodeposition, subsequently forming the TiO2 layer by dipping in the 0.05 M or 0.005 M TiCl4 solution. Their morphological, crystalline, optical and photoelectrochemical properties of the developed films and composed DSSCs were evaluated exploring the field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectrophotometer and solar simulator. In particular, the fill factor of pure WO3 coated SnO2 IO, 0.005 M TiCl4 treated WO3/SnO2 IO and 0.05 M TiCl4 treated WO3/SnO2 IO existed in the similar value of approximately 32%. On the other hand, the TiO2 coated samples exhibit the more enhanced absorption and photocurrent, compared to that of pure WO3/SnO2 IO, resulting in the high conversion efficiency. This points out that the proper coating of TiO2 layer on the WO3 photoelectrode can induce to the high dye adsorption as well as the suppressed charge recombination, granting the possibility of the challenging photoelectrode.