Efficient methylene blue degradation with spray-deposited ZnO, and V-doped ZnO thin films photocatalysts

This study presents a comprehensive analysis of the structural, microstructural, photoluminescence (PL), electrical, optical, and photocatalytic properties of vanadium-doped ZnO [2, 5, 10, and 15%] thin films. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the structural and microstructural changes, revealing degradation of crystallinity confirms the substitution of Zn²⁺ ions by V³⁺ ions and changes the shape of morphology with vanadium doping. Photoluminescence studies indicated a significant increase in defect-related emissions, suggesting enhanced electron–hole pair separation. Electrical measurements demonstrated improved conductivity in V doped ZnO films, attributed to vanadium's role in promoting charge carrier mobility. Optical analyses indicated a slight blue shift in the absorption edge, reflecting an increase in the optical bandgap of V doped ZnO compared to undoped ZnO; however, the absorbance in the 300–400 nm range was largely unaffected by vanadium doping, which does not represent enhanced light absorption capabilities. Instead, the blue shift suggests changes in the energy levels that may influence photocatalytic activity. Photocatalytic performance, assessed through the degradation of methylene blue solution under UV light irradiation, showed that 10% Vdoped ZnO thin films exhibited superior activity compared to other V doped ZnO films. These findings underscore the potential of V-ZnO thin films for advanced optoelectronic applications.