Exploring the interplay of structural, photoluminescence, mechanical and dielectric characteristics for Er₂O₃/barium titanate borate glasses

The effects of erbium (III) oxide (Er₂O₃) on the structural, photoluminescence, mechanical, and dielectric characteristics of glass (70 − x)B₂O₃ + 10BaTiO₃ + 20Li₂O + xEr₂O₃ where (x = 0, 0.25, 0.50, 0.75, and 1 mol%) have been explored. The melt quenching technique was used for manufacturing borate glasses with various Er₂O₃ concentrations. The FTIR spectra exhibit many absorption bands at various wavenumbers, which are associated with the vibrational modes of the borate network and the Ba²⁺, Li²⁺, and OH groups. The photoluminescence was examined through the excitation of the prepared glass samples by a helium–cadmium laser with a wavelength of 325 nm; the peak of the emission transition, which ranges from ⁴S_3/2 to ⁴I_15/2 at 543 nm, is most intense, and its intensity increases as the amount of Er³⁺ ions increases. The mechanical investigations demonstrated that adding rare earth ions changed the network structure of these glasses, causing the longitudinal velocity (V_L) to decline from 6415.4 to 5950 m/s and the shear velocity (V_S) to decrease from 3528.9 to 3281.5 m/s. The dielectric studies showed that the dielectric constant and the electrical conductivity increase with increasing Er₂O₃ up to 0.5 mol%; after that, they reduce, while the dielectric loss decreases noticeably at low frequencies as the concentration of Er³⁺ ions increases.