Effect of rGO Layering on the Structural, Optical, and Magnetic Properties of Sol-Gel Spin-Coated V-, Ce-, and Mn-Doped NiO Thin Films

V-, Ce-, and Mn-doped NiO/rGO bilayer nanocomposite thin films were prepared by the sol-gel spin-coating method. The structural, optical, and magnetic properties of the thin films have been investigated by XRD, XPS, Raman, SEM, UV-visible spectra, photoluminescence (PL) spectra, and SQUID-VSM analysis. The XRD patterns revealed the polycrystalline nature of the NiO thin films and the rGO layering decreased the crystallite size. The binding energy of all the thin films have been calculated using XPS spectra, confirming the cubic structure of NiO. Raman spectra analysis revealed the presence of increased defects corresponding to rGO in the layered films. rGO layering changed the surface morphology of all the doped films. Higher transmittance values have been observed for all the NiO and rGO layered NiO thin films in the visible and IR regions. The layering and doping changed the band gap values significantly. A PL quenching was observed in the rGO layered undoped and doped NiO thin films. Analysis of the magnetic properties revealed the increased values of saturation magnetization and magnetic moment in the rGO layered thin films.