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

In this work, Ni(II) carboxylate and Ga(III) beta-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 254 nm UV light. Subsequently, the photodeposited films were annealed at 350, 650 and 950 degrees 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 D-5(0) 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.