Effect Bi2O3 on the physical, structural and radiation shielding properties of Er3+ ions doped bismuth sodiumfluoroborate glasses

Er3+ ions doped Bismuth sodiumfluoroborate glasses with varying Bi2O3 content (0−50 in wt%) have been prepared following the melt quenching technique. The density, molar volume, FTIR and UV-Visible studies have been used to determine physical and structural properties of the prepared glasses. The FTIR studies explores that, addition of Bi2O3 helps the progressive conversion of [BO4] units into [BO3] units thus lead to the creation of non-bridging oxygens (NBOs). The boron‑boron separation(), oxygen packing density(OPD), bond density(nb) and calculated Poisson's ratio (μcal) values are found to decrease with the addition of Bi2O3thus reveal the fact that the network connectivity decreases due to the formation of non-bridging oxygen sites and the glass network becomes less tightly packed. Further, ionic nature of the Er3+ − metal ligand bond was identified from the measured optical basicity (Λth), covalent and ionic characteristic factors, and bonding parameter (δ) values.The observed variations in the optical electronegativity, basicity, metallization criterion and optical band gap energy (Eg) values have been discussed in terms of the structural changes that takes place due to the addition of Bi2O3 into the B2O3 network. Additionally, radiation shielding properties of the prepared glasses have been studied in the energy range 0.015-15 MeV. The mass attenuation coefficient has been calculated using MCNP5 code and XCOM software. The MCNP5 results match most of the XCOM data very well. Further, the effective atomic number, mean free path and half value layer (HVL) for the titled glasses were computed. The mass attenuation coefficient and the effective atomic number were found to progressively increase with the increase in the Bi2O3 content. The addition of Bi2O3 led to decrease the half value layer which means that more Bi2O3 content enhances the radiation shielding performance for the prepared glasses.