Résumé:
TiO2 thin films were prepared on glass and ITO substrate by sol–gel process. Their
structural and optical properties were examined of different steeping at various
calcination temperatures. The films were characterized with X-ray Diffractométre,
DSC, fluorescence X spectroscopy, UV-VISIBLE spectroscopy, optical
microscopy and Fourier transform infrared spectroscopy (FTIR). The XRD
patterns show that the xerogel of TiO2 are amorphous, and they transform into the
anatase phase from 350°C, and we notice the appearance of the phase brookite
after 400°C. In the case of the sample obtained with 400°C and 10 steepings , we
observe the appearance of the phase rutile , normally this one must appear with
800°C. The crystallite size of TiO2 thin films is increased with increasing
calcination temperature. The color of the thin layers obtained varies according to
the temperature of annealing and of the number of steeping. The thickness varies
between 20–285nm. The thermal analysis of the powder shows that the
crystallization of TiO2 is from 400°C. The thin layers of TiO2 are transparent in the
visible and opaque in UV, and this some are the temperature of annealing and the
number of steeping. The increase in the number of steeping returns the layers
opaque, what minimizes their transmission.
