A new method for controlling structural, electrical and optical properties of phosphate glasses, containing transition metal ions (TMIs)

Abstract In this study, glassy samples with a composition of 40P2O5–10V2O5–(50−x) Li2O–xNa2O, (x = 5–45 mol%), were prepared and their structural, electrical, and optical properties were investigated for the mixed alkali effect (MAE). The density of the samples displayed nonlinear variation with Na2O content (x mol%), which confirmed the existence of the MAE. It was found that the conductivity in the present glassy system is more ionic rather than electronic, and the minimum dc conductivity at x = 25 mol% is due to the MAE on ionic conductivity. Some optical parameters such as indirect allowed optical band gap, Urbach energy, refractive index, dielectric constant, reflection loss, molar refraction, and electronic polarizability were evaluated from the absorption and reflection spectra. The values of the optical band gap showed nonlinear behavior upon substitution of Li2O by Na2O with a maximum at x = 25 mol%, which supported the existence of the MAE in the optical properties.