Spray Pyrolysis Preparation And Hydrophylicity Of Titanium Dioxide Film

A comprehensive introduction of photocatalitic and super hydrophilic material, TiC>2, was presented in this paper. It had many great merits such as excellent optical properties, low-cost and easiness to handle which offered promising prospects in the filed of self-cleaning, anti-fog and so on.The hydrophilicity of TiO2 was influenced by many factors such as crystal structure, surface morphology, band gap, etc. Preparing method and doping element would take effect on the properties of the film.The spray pyrolysis method has large application potency to be a method to prepare the economical thin films for its unsophisticated equipment, low-cost and high deposition rate which are great advantages if the technique is to be scaled up for industrial applications.TiO2 thin films with super hydrophilicity were deposited onto soda-lime glass using the spray pyrolysis method, and the films doped with different content of Fe3+ or Zn2+ were also prepared. The crystal structure and surface morphology were characterized by XRD, SEM and AFM. The optical properties were characterized by uv-vis transmission spectrum. The hydrophilicity of the films was measured by a contact angle meter. And the mechanism of the film formation during the spray pyrolysis procedure was also discussed.The results turned out that the crystal structure was changed by the variation of the deposition temperature and annealing time. The surface morphology was greatly influenced by the Spray parameters which atomized the precursor droplet in different diameters and different intensities.When the droplets were in large diameter, the surface morphology would be more rough and heterogeneous. The surface morphology would be porous when the droplets were too small. It was found that the surface would be more smooth and homogenous when the droplets were in the middle scale. The hydrophilicity measurement shows that the smooth and homogenous surface of the TiO2 film showed to favor water spreading.The influence of the transitional metal ion, Fe3+ and Zn2+, was discussed. Fe dopent can be easily put into the matrix of TiO2 and hardly inflects the crystal structure or surface morphology. It can decrease the band gap of the thin film effectively so that it will improve the hydrophilicity of the thin film. Zn dopent may change the crystal structure while the surface morphology becomes rough. And the band gap remains high. So the hydrophilicity of the thin film decreased.It shows that the spray pyrolysis method can effectively produce TiO2 thin films with superhydrophilicity and offers an extremely easy way to dope films with other element. The analysis results in this work would be significant for reasonable utilization of spray pyrolysis deposition.