Green chemistry preparation and characterization of borosilicate glass doped with dysprosium using degraded silica gel for white-light emission

Abstract

This study focuses on the preparation and characterization of dysprosium (Dy³⁺)-doped borosilicate glass, using degraded silica gel (DSG) as a network former instead of high-purity silica. The glasses were synthesized using the melt quenching method at 1200 °C and the chemical formula (69-X)B₂O₃–18Li₂O–12BaO–XDSG-1.0Dy₂O₃, where X represents the concentration of degraded silica gel. The resulting glasses absorbed photons across ultraviolet, visible, and near-infrared wavelengths. The optimal DSG concentration for maximum photoluminescence was determined to be 10 mol%, which produced a color-correlated temperature (CCT) range of 4077–4649 K, exceeding the warm CCT threshold of 4000 K. The CIE color coordinate chart suggests that these samples are suitable for laser and white-light applications. The I–H model (with S = 6) confirmed dipole–dipole interactions during the energy transfer between Dy³⁺ ions. The glasses exhibited lifetimes in the millisecond range. Additionally, we prepared glass samples with varying Dy₂O₃ content in a suitable host (10Silicagel XDy glasses), maintaining the optimal DSG concentration at 10 mol%. The photoluminescence showed clear emission characteristics of Dy³⁺, closely resembling the radioluminescence spectra. Under excitation at λ_Ex = 387 nm, the developed glass exhibited two strong emission peaks at 576 nm (⁴F_9/2 → ⁶H_13/2) and 484 nm (⁴F_9/2 → ⁶H_15/2). The results showed that the glass doped with 1.0 mol% Dy₂O₃ had the highest emission intensity, confirming that degraded silica gel is a promising alternative to high-purity SiO₂ for producing efficient, luminescent, and environmentally friendly white-light optical materials.