Er2O3/P2O5 bismuth phosphate glass substitution: Preparation, optical, physical in nature and radiation-shielding characteristics

In this work, a series of phosphate glasses doped with varying concentrations of erbium oxide (Er₂O₃) was synthesized via the melt–quench method. The samples, coded as Er-X (where X denotes the Er₂O₃ mol% content), revealed systematic structural and optical modifications with increasing erbium concentration. Substitution of P₂O₅ by Er₂O₃ enhanced the density and reduced the molar volume. The optical band gap values decreased from 3.87 to 3.61 eV (direct) and from 3.65 to 3.18 eV (indirect), indicating stronger electronic interactions. Meanwhile, the electronic polarization increased from 2.27 × 10⁻²⁵ to 2.38 × 10⁻²⁵ cm³, the refractive index rose from 2.24 to 2.35, and the metallization criterion declined from 0.42 to 0.39. A reduction in optical transmittance (0.74–0.72) and an increase in reflection loss (0.146–0.162) were also observed with higher Er doping. Radiation shielding efficiency was assessed through Phy-X software and Monte Carlo simulations. The linear attenuation coefficient (LAC) increased with Er content, reaching 96.551 cm⁻¹ for Er-1.0 at 0.015 MeV, while the half-value layer (HVL) decreased to 8.193 cm at 15 MeV. These results demonstrate that erbium-enriched phosphate glasses possess enhanced shielding capability, making them promising candidates for ionizing radiation protection applications.