Synthesis, Characterization, and Photocatalytic Performance of (Eu, Ni) Co-Doped ZnO Thin Films for Environmental Applications

Abstract

Undoped and Ni-Eu co-doped ZnO thin films were successfully fabricated via spray pyrolysis at 400°C. The impact of co-doping on the structural, morphological, electrical, and optical properties of the thin films was thoroughly investigated. X-ray diffraction (XRD) analysis confirmed the absence of secondary phases and verified the successful incorporation of dopant ions into the ZnO lattice. Morphological examination revealed enhanced crystallization and a more uniform surface following the incorporation of nickel. Spectral studies in the UV-Vis region were conducted to determine the optical band gap of the synthesized ZnO films, indicating a slight decrease in bandgap values and volume and surface energy losses (VELF and SELF) with increasing Ni doping concentration. Photoluminescence spectra exhibited emission peaks in the UV region around 415 nm and broad visible emissions spanning 450-650 nm for all samples. Electrical characterization using Hall Effect measurements confirmed n-type electrical conductivity in all prepared films, as evidenced by the observed negative Hall coefficients. The co-doped ZnO thin films, particularly those incorporating Ni-Eu, show promise for applications in electronic and optoelectronic devices. Additionally, we investigated the photodegradation of green malachite under a UV lamp. Remarkably, the results demonstrated degradation rates of 93% within 2 hours, showcasing promising potential for practical applications.