Study on the effect of bismuth oxide on the structural, optical and dielectric properties of strontium phosphate glasses

The melt-quenching technique was used to prepare strontium phosphate glasses with bismuth oxide. The impact of replacing Bi3+ with Sr2+ on density (d), molar volume (V-m), and glass transition temperature (Tg) was investigated. The FTIR spectra revealed that the structural units of the samples consisted of [BiO3], [BiO6], [PO3], and [PO4]. UV-visible spectroscopy was used to study the optical transmittance, energy band gap (E-opt), and Urbach energy (E-tail). The Wemple-Didomenico model successfully described the dispersive behavior of the refractive index. Impedance spectroscopy is utilized to determine the electrical and dielectric properties. The AC conductivity followed Jonscher's universal power law, and it was observed that as the concentration of Bi2O3 increased, the frequency exponent (s) decreased. The dielectric constant (epsilon') and dielectric loss (tan delta) were found to be frequency and composition dependent. The parameters describing the dispersion of dielectric constant are obtained through the Cole-Davidson relation.