Effect of cerium doping on enhanced UV-shielding capacity of nanostructured ZnO thin films

This paper includes the contribution of cerium (Ce) dopant in enhancing the UV-shielding capacity of nanostructured zinc oxide (ZnO) thin films. Nanoparticles synthesized through the sol-gel process were utilized to create thin films on glass substrates, employing the spin-coating technique for deposition and Ce concentration was adjusted within the range of 1 to 10 mol%. All nanostructures were identified through X-ray diffraction measurements as having a hexagonal wurtzite structure, predominantly oriented along the (002) plane. Scanning electron microscopy revealed uniformly distributed nano-grains and pores throughout the film surface, while energy-dispersive X-ray spectroscopy verified the zinc, cerium, and oxygen contents of the nanostructures and their stoichiometric composition. UV-Visible spectroscopy showed that Ce-doped ZnO (CZO) nanostructures had over 85% transmittance within the visible spectrum. The optical band gap exhibited a declining trend with increasing Ce concentration in ZnO, reaching a minimum value of 3.16 eV at 10-mol% Ce doping. Optical analysis revealed that ZnO doped with 5-mol% Ce (5.15%) in the UVA region and ZnO doped with 4-mol% Ce (19.79%) in the UVB region had higher shielding capacity than undoped ZnO. A comparative evaluation of UV-shielding ratios indicated that 4-mol% Ce doping was optimal in this study, offering superior shielding in both UVB and combined UVA/UVB regions. This study suggests that CZO nanostructures hold significant promise for applications requiring effective UV shielding and enhanced optical performance.