Effect of Gd doping on structural, morphological, optical, photocatalytic, and antibacterial properties of NiO thin films

In this study, the influence of Gd doping on the properties of NiO thin films deposited onto glass substrates by spray pyrolysis was investigated. The structural, surface morphological, optical, photocatalytic and antibacterial properties were examined in NiO films doped with different Gd concentrations (Ni1-xGdxO; x = 0,0.02, 0.04 and 0.06), revealing significant changes in their structural and surface morphological characteristics. As observed in both XRD and SEM analysis, the size of crystallites reduces as Gd content rises. Raman spectroscopy reveals distinctive peaks corresponding to the Ni-O first and 2-order phonon bands, which show a systematic shift in peak positions with Gd doping confirming successful doping. Optical measurements of Gd-doped films showed variation in transmittance and band gap energies compared to the pure NiO. Photoluminescence reveals a reduction in intensity with doping, indicating a decrease in the radiative recombination rate. The Gd-doped NiO films exhibit enhanced degradation efficiency for Indigo carmine dye and also show improved antibacterial activity against E.coli and Pseudomonas. These findings highlight the potential of Gd-doped NiO films for applications in photocatalysis and antimicrobial materials.