Elaboration Of Electrode Materials Based On Metal-semiconductor By Electrochemical Method

Résumé: In this thesis, optimisation of parameters related to the synthesis metal oxide semiconductor nanostructures (ZnO and Cu2O) by the electrochemical method were investigated, in order to enhance their performance by applying a variety of strategies. Two applications have been developed in this thesis. The first application focused on the construction of a p-n heterojunction based on Cu2O/ZnO thin film for further application in thin film solar cell. Then, a photocatalytic water purification study has been carried out under UV and solar radiation for the three dyes (MB), (MO) and (CR). In order to improve the performance of ZnO in the Cu2O/ZnO junction, doping ZnO lattice with copper ions with two oxidation states (+1 and +2) has been performed. Furthermore, the properties of the Cu2O/ZnO and Cu2O/Cu-doped ZnO heterojunctions prepared were studied. As a results a good performance was observed for the Cu(+2)-doped-ZnO based device due to the improvement of the charge transport properties between ZnO and Cu2O. Concerning the second application, two methods have been developed. The first is based on the use of copper doped ZnO thin films as catalysts under UV irradiation. The results showed that the doping process improves photocatalytic performance by increasing the lifetime of the electron-hole pair. The second method was carried out with the aim of replacing the expensive artificial light sources by natural source, so for better exploitation of the solar radiation, the doped ZnO coupled with Cu2O was used to make heterojunction. As a results the photocatalytic degradation experiments under solar radiation were very satisfactory.

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