Infection of Oxygen Vacancy at the TiO₂ Surface for Film Electrode Rup₂P/TiO₂/ITO Photo-Induced Charge Transfer

Abstract

The surface properties of TiO2-X (X=5, 10, 20, X=[NaOH] (in mol •L-1)) samples prepared by modification of hydrolyzed TiCl4 were studied. The surface-sensitized Ru(phen)2(PIBH) (Rup2P) (phen= phenanthroline, PIBH=pyridyl benzimidazole hybrid) film electrodes Rup2P/TiO2-5/ITO (indium tin oxide), Rup2P/TiO2-10/ITO, and Rup2P/TiO2-20/ITO were prepared. Among the three films, the photovoltaic properties of Rup2P/TiO2-10/ITO were the best and those of Rup2P/TiO2-5/ITO were the worst. The band structures, and properties on the surfaces of Rup2P and the three TiO2 samples were analyzed using absorption spectra, surface photovoltage spectra, photoluminescence spectra, and photocurrent action spectra. The photo-induced charge transfer process was studied by cyclic voltammetry under irradiation and photocurrent action spectra. The results revealed the oxygen vacancy at the TiO2 surface was very important for the photo-induced charge transfer process of Rup2P/TiO2-X/ITO. The photocurrent mechanism of Rup2P/TiO2-X/ITO is discussed.