Composition-dependent variations in structural, optical and shielding characteristics of CuO-containing borate glasses

This study investigates the structural, optical, and radiation shielding properties of 55B 2 O 3 - 15ZnO - (30−x)Li 2 O - xCuO glasses (x = 0, 2, 4, 8 mol%) synthesized via melt-quenching. XRD confirmed the amorphous nature. While density and molar volume analysis revealed a non-linear trend with CuO doping. FTIR analysis revealed structural changes due to the substitution of Li 2 O with CuO. UV-Vis spectra exhibited characteristic Cu 2+ d-d transitions (700–800 nm). Tauc plots showed bandgap narrowing (direct: 3.33 - 2.68 eV; indirect: 2.80 - 2.01 eV) and Urbach energy increased from 0.45 to 0.54 eV). Photoluminescence revealed Cu 2+ -related emissions (401–543 nm). The Makishima-Mackenzie model predicted a decrease in elastic moduli (E, K, S, L) due to network fragmentation. Radiation shielding performance improved significantly, with CuO reducing the half-value layer by 27% at 15 keV and increasing the mass attenuation coefficient (μ/ρ) by 46% at low energies, driven by high atomic number (Z = 29). Advanced parameters (EBF, EABF, ACS, ECS) demonstrated optimal shielding at 4 – 6 mol% CuO, balancing photoelectric enhancement and Compton scattering suppression. These findings position CuO-doped borate glasses as multifunctional materials for photonic and radiation shielding applications, with tunable properties governed by Cu 2+ coordination and network dynamics.