Optimization, experimental and Phy-X/PSD simulation study on optical and radiation shielding performance in Bi₂O₃-modified ZnO-B₂O₃ glass system

Zinc borate glasses have experienced growing attention recently owing to their remarkable combination of optical, thermal, and chemical characteristics. Nevertheless, certain drawbacks in its optical performance persist, particularly a reduction in the optical band gap caused by the incorporation of high concentrations of heavy metal oxides. Hence, a new composition in the bismuth zinc borate glass, xBi₂O₃-(45-x)ZnO-55B₂O₃, was fabricated using the conventional melt-quenching method. The density and molar volume increased from 3.19 to 4.28 g/cm³ and 23.48 to 31.00 cm³/mol, respectively. Simultaneously, the direct and indirect band gaps decreased, shifting from 3.51 eV to 1.48 eV and from 3.28 eV to 0.92 eV, respectively. The estimated refractive index increased from 2.27 to 3.00 with increasing Bi₂O₃ concentration. Notably, the highest optical transmittance was observed in the glass containing 1 mol% Bi₂O₃, which also exhibited the highest PL intensity, with an emission maximum at 521 nm. Radiation-shielding parameters were systematically evaluated over a broad photon-energy range using Phy-X/PSD simulations. Increasing Bi₂O₃ content enhanced the radiation attenuation performance, with the 15 mol% Bi₂O₃ glass exhibiting the highest shielding capability. Overall, the results demonstrate a trade-off between optical and radiation-shielding performance, indicating that low Bi₂O₃ content favors optical performance, whereas higher Bi₂O₃ content provides superior radiation attenuation. These glasses, therefore, show potential as lead-free multifunctional materials for optical and radiation-shielding applications.