Nanocrystalline TiO2 thin films on soda-lime–silica glass by using a titanium naphthenate precursor

TiO2 thin films were prepared on soda-lime–silica slide glasses by spin coating-pyrolysis process using titanium naphthenate as a starting material. Precursor films were prefired at 500 °C for 10 min in air and finally annealed at 500, 550 and 600 °C for 30 min in air, followed by rapid cooling. Crystallinity of the TiO2 films was investigated by X-ray diffraction (XRD) analysis. A field emission-scanning electron microscope and an atomic force microscope were adopted for characterizing the surface morphology and the surface roughness of the TiO2 films. After final annealing at 550 and 600 °C, the XRD patterns consist of only anatase peak of TiO2 film. Films annealed at 500 and 550 °C exhibited flat surfaces. On the contrary, with the increase in annealing temperature to 600 °C, the TiO2 film showed growth of three-dimensional needle-shaped grains. For all samples, high transmittance at visible range was obtained by ultra violet–visible–near infrared spectrophotometer.