Sol-gel derived Li and Mg incorporated nickel oxide particles: An investigation on structural and optical properties

Abstract In this study, NiOx, Li:NiOx, and Li,Mg:NiOx powders (Li0.05MgaNi(0.95-a)Ox, a: 0.00; 0.05; 0.1; 0.15; 0.30) were produced by sol-gel method. Preformed powders were annealed at 350 °C, 500 °C, and 650 °C to monitor structural changes. Functional groups, compositions, phase structures, elemental analysis, morphology, and optical properties were investigated by Fourier transforms infrared spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and photoluminescence measurements (PL), respectively. The incorporation of Li+ and Mg2+ into NiOx structure was successfully accomplished as seen on XPS results. Crystallite size decreased upon increasing dopant concentration. All of the powders, with bi-exponential decay curves, exhibited maximum emission peak at 550 nm under the excitation at 362 nm. A decrease in both emission based intensity and average decay time values was observed at addition of Li+ and Mg2+ into structure with respect to the pristine NiOx.