Synthesis and characterization of Fe2O3–TiO2 thin films grown by the sol–gel method

Abstract

We report the synthesis of Fe 2 O 3 -TiO 2 thin films obtained with the sol-gel method by varying the Fe 2 O 3 wt% in the growing solution to 0, 25, 50 and 75. Glass was used as substrate. The films were characterized by means of the FTIR, Auger and UV-Vis spectroscopies. The results show that the Fe 2 O 3 -TiO 2 films are partially hydroxylated, the Fe incorporation into TiO 2 modify the optical properties by means of the Ti +4 reduction to Ti +3 species, and that the Fe concentration in the films increases when the Fe 2 O 3 concentration in the growing solution is increased.1 Introduction In recent years, Titanium Dioxide (TiO 2 ) has been extensively studied for its interesting electronic, photocatalytic and electrochemical properties [1][2][3]. In photocatalysis, the TiO 2 is the most promising catalyst due to its high efficiency, stability and low cost. Nevertheless, some disadvantages of TiO 2 for industrial applications are the necessity of filtration after the degradation process and that it is photoactive in the near UV range. To overcome the former disadvantage the TiO 2 can be prepared in thin film form which can be used in surface water and ground water purification. To skip the later disadvantage some researchers have proposed to dope the TiO 2 with transition metal ions in order to extend the absorption threshold to the visible light region. The sol-gel process has been used to prepare polymeric materials such as metal oxides. Its advantage is that during the first stage of the reaction it is possible to incorporate active metals, so that the product will be a material with the metal dispersed on the oxide. In addition, some part of this metal is incorporated in the oxide matrix modifying the physical, chemical, optical and photocatalytic properties [4].In this work we report the synthesis of Fe 2 O 3 -TiO 2 layers grown by the sol-gel method on glass substrates and the effect of varying the Fe 2 O 3 concentration in the growing solution on the chemical composition and optical properties of the layers. The characterization techniques used in this work are FTIR, UV-Vis and AES.