Study on the photochemical preparation of nickel gallium oxide spinel doped with Eu(III) ions from carboxylate and β-diketonate complexes and the evaluation of its optical properties

Abstract

In this work, Ni(II) carboxylate and Ga(III) β-diketonate complexes, were studied as precursors for the photochemical deposition of ternary metal oxide thin films with different levels of Eu(III) doping. Diluted solutions of these complexes were mixed, spin-coated on silicon(100) and irradiated at room temperature with a 254nm UV light. Subsequently, the photodeposited films were annealed at 350, 650 and 950°C. The photochemistry and annealing of these films was monitored by Fourier transform infrared spectroscopy. The obtained samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and UV–vis spectroscopy. The results showed the formation of spinel-type structures (NiGa2O4). The prepared phosphors under UV irradiation revealed red luminescence, which was attributed to transitions from the 5D0 excited state to the 7Fj ground states of the Eu3+ ions. The intensity of the photoluminescence decreases upon Eu doping, and the performance of these emissions depends strongly on the surface structure and morphology of the photodeposited films.