UVB Luminescence and Structural Insights of Gd3+-Activated Na2O-Ga2O3-B2O3-Y2O3 Glasses for Applications in Phototherapy Devices.

In this work, the UVB emission of Gd3+ ions incorporated into the Na2O-Ga2O3-B2O3-Y2O3 glass matrix was thoroughly investigated by varying the concentration of Gd2O3. Photoluminescence measurements revealed a strong and well-defined emission peak at 312 nm, related to the 6P7/2 → 8S7/2 transition of Gd3+ ions under 273 nm excitation. Notably, the emission intensity increased nearly threefold as the Gd2O3 concentration rose from 0.2 to 0.8 mol%. The results were examined using Judd-Ofelt analysis and supported by decay kinetics, infrared spectra, ESR spectra, and DSC studies. The enhancement of luminescence was mainly attributed to reduced phonon losses associated with Ga2O3. However, a decline in emission intensity at 1.0 mol% Gd2O3 was observed, which was ascribed to ion clustering and cross-relaxation processes. Overall, this study demonstrates that tailoring the Gd2O3 concentration provides an effective approach to enhance UVB output in alkali-yttria-gallium-borate glasses. The composition containing 0.8 mol% of Gd2O3 is identified as a promising luminescent material for phototherapeutic applications, particularly in the treatment of skin disorders such as psoriasis and vitiligo, and for use in the fabrication of phototherapy devices.