Étude des propriétés photophysiques de tio2-sio2 en présence d’un colorant et son application

Abstract

This thesis focused on the study and characterization of SiO2 doped and undoped TiO2 photocatalytic thin films. The photocatalytic qualities of titanium oxide are limited by adsorption of the dye. The objective is to act on the physical and electrochemical properties of the TiO2 layer in order to improve the photocatalytic performances. In this work, we investigated the effect of the crystalline structure of TiO2 anatase as a function of the number of thin layers of TiO2 and as a function of the annealing time and then their ability to adsorb the methylene blue solution in the process purpose of producing color filters from the photocatalytic process. The photoinduced properties of TiO2 could be modified when this compound is embedded in a silica matrix. These composite films influence photocatalysis. SiO2 doping increases the sensitization of the obtained material. Analyzes made by XRD and RAMAN techniques indicate that the anatase phase is dominant. AFM microscopy shows good homogeneity as well as the absence of cracks on all the deposits of prepared layers. UV-Visible spectroscopy indicates that all films are transparent in the visible and opaque in the UV. An adsorption study of a dye which is methylene blue was made on a photocatalyst which is TiO2 and this for a subsequent embodiment of an optical component which is the color filter. The results obtained during this study showed that the adsorption capacity varies according to the number of thin layers deposited and as a function of the exposure time under UV light. The increase in the doping rate leads to a decrease in adsorption of the dye and with the increase of the annealing temperature for 10% and 20% of SiO2. The result obtained by the DRX technique shows the appearance of the anatase phase and the photoelectrochemical results show that the photo activity is improved. TiO2 photocatalysts doped with SiO2 increase the adsorption rate of the dye and this behavior confirms the physicochemical properties reported in this dissertation