Structural, dielectric and optical properties of Ta2O5-Bi2O3-P2O5phosphate glasses

Abstract

Glasses with the formula 5Ta2O5-xBi2O3-(95-x)P2O5for 10 ≤x≤ 20 mol% were prepared using the standard melt-quench method and identified using X-ray diffraction, Differential Scattering Calorimetry, and Infrared spectroscopy. Furthermore, the dielectric and optical characteristics were determined. The glass transition temperature (Tg) increases linearly with bismuth oxide content, from 524 °C forx= 10 mol% to 582 °C forx= 20 mol%. When the amount of Bi2O3in the system increases, the density rises and the molar volume (VM) decreases. The Infrared spectroscopy shows the presence of BiO6and PO3structural groups and reveals the depolymerization of the phosphate links by the creation of the Bi–O–P groups. Replacing P2O5by Bi2O3shows that the dielectric constantɛr' and dielectric losses tanδvary with the concentration of added Bi2O3. Optical characteristics of the investigated glasses were determined using UV–vis spectroscopy and the energy band gap has been estimated.