Role of the Gd₂O₃ increment on the cerium oxidation state and luminescence behavior in the CeF₃ doped silicoborate glass

This study aimed to investigate the effect of Gd₂O₃ on the cerium oxidation state and studied their luminescence in the silicoborate glass. Glass samples of a silicoborate glass containing cerium fluoride were prepared by doping the glass with varying amounts of Gd₂O₃ in the chemical formula xGd₂O₃: 40Na₂O: 5SiO₂: (54.5)B₂O₃: 0.5CeF₃ (x = 0.0, 2.5, 5.0, 7.5, and 10.0 mol%). Density and refractive index tend to increase with increasing Gd₂O₃ content, whereas molar volume decreases. High-resolution XPS spectra confirm the chemical composition in the glass structure and found that the B1s and O1s regions illustrated more BO₄ and bridging oxygen, respectively. X-ray absorption near edge structure (XANES) at the Ce LIII-edge was used to investigate the proportion between trivalent cerium (Ce³⁺) and tetravalent cerium (Ce⁴⁺). The ratio of Ce³⁺/Ce⁴⁺ decreased with the addition of Gd₂O₃. A higher concentration of Gd₂O₃ content showed more Ce⁴⁺ related to the reduction of photoluminescence and X-ray-induced luminescence spectra. Alpha-induced luminescence was used to calculate the light yield of the 7.5Gd:0.5CeF glass. Decay time was measured by pulsed light sources at 286 nm and X-ray excitation.