The effects of bismuth substitution on structural, elastic, DC conductivity and radiation shielding properties 98[20Li₂O-xBi₂O₃-(80-x)B₂O₃]-2Ag

This study highlights the transformative effect of bismuth substitution on the structural, elastic, electrical and radiation shielding properties of the 98[20Li₂O-xBi₂O₃-(80-x)B₂O₃]-2Ag glass system (x ranging from 3 to 11 mol%). Bismuth’s role as a network modifier introduces significant changes to the glass matrix, influencing its overall performance and suitability for advanced applications. The need for effective radiation shielding arises from the increasing use of ionizing radiation in various fields, including medicine, industry, and scientific research. Ionizing radiation, which includes x-rays, gamma rays, and high-energy particles which poses significant risks to human health and materials due to its ability to ionize atoms, damaging biological tissues, and degrade structural integrity. In medical applications, for instance, radiation is widely used in diagnostic imaging and cancer treatment, necessitating materials that can protect patients and medical personnel. Consequently, the development of advanced radiation shielding materials with high attenuation efficiency, low thickness requirements, and durability has become a critical area of research. Structurally, bismuth plays a critical role in altering the glass network. FTIR spectroscopy reveals that Bi₂O₃ introduces both non-bridging oxygens (NBOs) and bridging oxygens (BOs), with the presence of BiO₆ and BO₃ groups indicating higher NBO content, while BiO₃ and BO₄ groups signify increased BOs. This shift in the NBO/BO ratio reflects significant changes in network connectivity. The molar volume and density increase notably between x = 7 and x = 9 mol%, attributed to the formation of additional NBOs, which expand the glass matrix and modify its structural integrity. In terms of elastic properties, bismuth substitution reduces structural rigidity. Longitudinal and bulk moduli decrease at x = 7 mol%, indicating a softer glass network due to the increased prevalence of NBOs. Furthermore, the maximum Kbc/Ke ratio and the highest ring parameter observed at x = 7 mol% suggest that bismuth significantly alters the glass's ring structure, highlighting its impact on the elastic response of the material. Bismuth also influences the electrical conductivity of the glass. DC conductivity reaches its lowest value at x = 9 mol%, which corresponds to a critical concentration where the structural changes induced by bismuth disrupt ion mobility. This suggests that bismuth affects the pathways available for ionic conduction, leading to reduced conductivity at higher concentrations. Radiation shielding properties of the glass improve substantially with higher bismuth content. Phy-X/PSD simulations reveal that bismuth enhances shielding performance across a wide photon energy range (15 keV to 15 MeV). The mass attenuation coefficient (MAC) increases with bismuth concentration, while the half-value layer (HVL) and mean free path (MFP) decrease, indicating more effective radiation attenuation. Additionally, the effective atomic number Zeff peaks at x = 11 mol%, confirming bismuth’s ability to enhance photon interaction probability and improve the protective performance of the glass. In conclusion, bismuth substitution exerts a profound impact on the structural organization, elastic properties, electrical conductivity, and radiation shielding capabilities of the glass system. These findings underscore bismuth’s potential as a key dopant for designing advanced materials with tailored properties for applications in radiation protection, optoelectronics, and other high-performance technologies. By addressing the pressing need for efficient radiation shielding materials, this research contributes to the safety and sustainability of radiation-intensive environments.