Preparation and optoelectronic properties of TiO 2 thin films codoped with iron and molybdenum

TiO 2 codoped with iron and molybdenum (Fe/Mo-TiO 2 ) thin films were deposited on glass substrate by RF magnetron sputtering, and calcining at 550 °C for 2 h. The films were characterized using SEM, XRD, Raman spectrum and UV-Vis transmission spectroscopy. The results show that the films are amorphous, and the appropriate amount of molybdenum doping is beneficial to the crystallization of the thin films. The particle size of the formed films increases with increasing the atomic ratio of molybdenum and iron. Under different preparation conditions, the band gap of the films are reduced relative to the intrinsic absorption of TiO 2 ( E g = 3.20 eV). Particularly, the value of the bang gap of TiO 2 films which were prepared by using the 2: 1 atomic ratio of molybdenum and iron has decreased significantly, and reaching 1.91 eV. When a dopant of 2: 1 atomic ratio of molybdenum and iron was employed, the Fe/Mo-TiO 2 films were optimum in hydrophilicity and photocatalysis. The films exhibit good photocatalytic activity as shown by the degradation rate of 75.4% for methylene blue solution after 4 h irradiation under UV lamp.