Optimisation des propriétés physico-chimiques et photocatalytiques des couches minces à base d’oxyde

Abstract

In this work, undoped and Ba-doped ZnO thin films were deposited on glass substrates by a simple and cost effectiveness successive ionic layer adsorption and reaction (SILAR) method. These films were investigated using various techniques. To optimize the quality of our films, we have studied the influence of dopant concentrations, deposition cycles number, and annealing temperature on film’s structural, morphological, optical, and photocatalytic properties. All samples exhibited a polycrystalline nature with wurtzite hexagonal phase. The X-ray diffraction patterns shows that the 5 wt. % Ba-doped ZnO crystallization is better than undoped samples, with a (100) preferred orientation. SEM images revealed that the films were well adherent and uniform. UV- Visible depicted that the transmittance of the films increased as increasing of Ba-doping concentrations, demonstrating improved optical transparency. The 5 wt.% Ba-doped ZnO films displayed the highest photocatalytic efficiency, achieving 95.78% degradation of MB under sunlight irradiation over 5 hours. This sample showed exceptional stability and reusability, retaining its performance over five cycles. On the other hand, 5 wt.% Ba-doped ZnO films deposited at different cycle numbers showed that an increase in deposition cycles led to better crystallinity at higher cycles. As a result, the photocatalytic efficiency improved to 93.51% at 15 cycles. Furthermore, the results showed that the process of annealing temperature at 450°C enhanced the crystallinity, the optical properties, and the photocatalytic efficiency of Ba-doped ZnO films, achieving 96.17% degradation of MB, and which gradually decreased to 94.89% after five successive cycles.