Effects of water-to-methanol ratio on the structural, optical and photocatalytic properties of titanium dioxide thin films prepared by mist chemical vapor deposition

The mist chemical vapor deposition method was used to synthesize pure anatase phase titanium dioxide thin films on glass substrates. The effects of water-to-methanol ratio on the structural, optical and photocatalytic properties of titanium dioxide thin films were investigated. Titanium dioxide films deposited by mist chemical vapor deposition were always anatase phase independent of the various water-to-methanol ratios investigated. From the GIXRD results, it was found that with the decrease of the water-to-methanol ratio, the growth of {001} facets was enhanced. The uniformity of the synthesized titanium dioxide thin films was characterized by field emission scanning electron microscopy and atomic force microscope. The highest surface roughness and surface area was obtained with a water-to-methanol of 0 %, corresponding to undiluted 100 % methanol. The transmittance of all anatase titanium dioxide films was higher than 70 % in the visible region. By decreasing the water-to-methanol ratio, the photocatalytic efficiency of the anatase titanium dioxide films exhibited an increasing trend. Due to the highest ratio of {001} facets and maximized surface area, the titanium dioxide films deposited with a water-to-methanol of 0 % have the optimum photocatalytic efficiency, with a high potential for photocatalyst applications.