Microstructural, photocatalysis and electrochemical investigations on CeTi2O6 thin films

The properties of sol-gel derived CeTi2O6 thin films deposited using a solution of cerium chloride heptahydrate and titanium propoxide in ethanol are discussed. The effect of annealing temperature on structural, optical, photoluminescence, photocatalysis and electrochemical characteristics has been examined. Lowest annealing temperature for the formation of crystalline CeTi2O6 phase in these samples is identified as 580 degrees C. The optical transmittance of the films is observed to be independent of the annealing temperature. The optical energy bandgap of the 600 degrees C annealed film for indirect transition is influenced by the presence of anatase phase of TiO2 in its structure. Fourier transform infrared spectroscopy investigations have evidenced increased bond strength of the Ti-O-Ti network in the films as a function of annealing temperature. The photoluminescence intensity of the films has shown dependence on the annealing temperature with the films fired at 450 degrees C exhibiting the maximum photoluminescence activity. The decomposition of methyl orange and eosin (yellow) under UV-visible light irradiation in the presence of crystalline CeTi2O6 films shows the presence of photoactivity in these films. The photocatalytic response of CeTi2O6 films is found to be superior to the TiO2 films. In comparison to crystalline films, the amorphous films have shown superior electrochemical characteristics. The 500 degrees C annealed amorphous films have exhibited the most appropriate properties for incorporation in electrochromic devices comprising tungsten oxide as the primary electrochromic electrode. (C) 2007 Elsevier B.V. All rights reserved.