Résumé:
In the following undertaking, we have dealt with both the annealing temperature effects and the addition of Sn and Al doping on the structural, morphological, optical, and photocatalytic proprieties of TiO2 thin films deposited by sol-gel dip-coating method onto glass and Si (100) substrates. For this reason, different investigative techniques were used such as XRD, Raman, SEM, AFM, UV-Visible spectroscopy, PL, XPS and the photocatalytic test. Studying the effect of the annealing temperature (450 and 500 °C) and the doping content (Sn and Al) on the TiO2/Glass film, we noted that the Sn doping deteriorates the crystallinity of TiO2 film, however the Al doping and the annealing temperature improve it. 500 °C is the optimum temperature to obtain a porous structure. The gap energy decreases with increasing Al content and annealing temperature. The Sn and Al dopants decrease the (e-/h+) recombination rate of TiO2/Glass films annealed at 500 °C. The photocatalytic results reveal that the two dopants Sn and Al improve the efficiency of TiO2/Glass, for the degradation of RhB under the UV light irradiation. Investigating the effect of high annealing temperatures (from 600 to 1000 °C) on the different properties of TiO2/Si(100) film, we concluded that the additional of Sn doping promote the rutile structure, while the additional of Al doping favorite the anatase structure. The surface morphology of TiO2/Si(100) films is compact while that of Sn:TiO2/Si(100) and Al:TiO2/Si(100) is porous. The TiO2/Si(100) films have an absorption edge in UV region but it shifts towards the visible region after the addition of Sn and Al elements. 600 and 1000 °C are the optimums annealing temperatures for a good photocatalytic efficiency under the visible light irradiation, of 1 at.% Sn:TiO2/Si(100) and 3 at.% Al:TiO2/Si(100) films, respectively.
