Enhanced 311 nm (NB-UVB) Emission in Gd2O3-Doped Pb3O4-Sb2O3-B2O3-Bi2O3 Glasses: A Promising Platform for Photonic and Medical Phototherapy Applications

A novel series of Gd2O3-doped Pb3O4–Sb2O3–B2O3–Bi2O3 glasses was synthesized via the conventional melt-quenching technique to explore their structural, thermal, and optical properties for potential photonic and medical phototherapy applications. X-ray diffraction and SEM analyses confirmed the amorphous and homogeneous nature of the samples, while their FTIR spectra revealed characteristic Pb–O, Sb–O, Bi–O, and B–O vibrational bands indicative of a stable glass network. Differential scanning calorimetry (DSC) demonstrated good thermal stability, suitable for high-temperature optical applications. Optical absorption and emission studies indicated the presence of prominent Gd3+ ion transitions, with a strong and sharp ultraviolet emission at 311 nm (6P7/2→8S7/2) when excited at 274 nm. The emission intensity and lifetime increased with Gd2O3 concentrations of up to 1.0 mol%, beyond which concentration quenching was observed. The optimized composition exhibited a reduced optical band gap and enhanced NB-UVB emission efficiency, suggesting efficient energy transfer with minimal non-radiative losses. These results establish the designed glass system as a promising multifunctional material for NB-UVB-based phototherapy, UV-laser generation, scintillation, and other next-generation photonic devices.