Crystallization, structural, and optical properties of the 2BaF2·Al2O3·B2O3 glass in the presence of Er2O3 and SiO2

This study investigates the crystallization behavior and optical properties of the 2BaF₂·Al₂O₃·B₂O₃ oxyfluoride glass in the presence of SiO₂ and Er₂O₃ compositions. Samples were synthesized using the melt-quenching method. The amorphous nature of the prepared samples was characterized through X-ray diffraction (XRD) analysis. Differential thermal analysis (DTA) was subsequently employed to determine the glass transition temperature (T_g) and crystallization temperature (T_c). The presence of SiO₂ and Er₂O₃ was found to enhance the glass forming ability and the crystallization temperature of the system. The optical bandgap was calculated by drawing Tauc plots from UV–Vis spectra. Notably, the presence of SiO₂ caused a red-shift in the UV-absorbance edge of the glass, and resulting in a decrease in the optical bandgap. Molecular structure was further studied by Raman and FTIR analysis. Based on the DTA curves, glasses were heat-treated and the resulting glass-ceramics were analyzed using XRD, Photoluminescence and field emission scanning electron microscopy (FESEM). XRD analysis confirmed the crystallization of the BaAlBO₃F₂ crystalline phase within the glass matrix. Furthermore, the recorded down-shifted and upconversion photoluminescence spectra indicated that the Er³⁺ doped glass-ceramics have stronger emissions compared to glasses.