Synthesis of eco-friendly borosilicate glass with Eu³⁺ dopants: Harnessing recovered silica gel waste for reddish-orange emission materials

In this study, recovered silica gel waste (RSGW) is used as a key raw material to create borosilicate glass doped with Eu³⁺ ions in a new and environmentally friendly way. The glass compositions were fabricated using the melt quenching method, with different amounts of RSGW and a constant 1.0 mol% Eu³⁺ doping concentration. The study shows that increasing the doping concentration of RSGW improves the glass density and rigidity while reducing the molar volume, indicating enhanced glass stability. Photoluminescence and X-ray luminescence analyses confirm that the optimal composition with 50 mol% RSGW exhibits the strongest emission. Based on the phonon sideband analysis, the host glasses have a phonon energy of 966.53 cm^{− 1}. An X-ray absorption near-edge structure (XANES) analysis showed that most of the europium ions were in the 3+ oxidation state. The CIE 1931 chromaticity investigation shows the x,y color coordinates at (0.645, 0.351) in the reddish-orange region. To optimize the doping concentration of Eu₂O₃, it was determined that a fixed concentration of 50 mol% RSGW created the most suitable mixture. Both luminescence emission spectra exhibit strong luminescence, with a peak emission wavelength of 615 nm (⁵D₀→⁷F₂), confirming concentration quenching in both photoluminescence and x-ray luminescence at a concentration of 1.0 mol%. The study explores potential applications of this novel material in photonics and suggests that this eco-friendly synthesis approach holds great promise for sustainable and efficient production of reddish-orange emission materials.