Regular Article

Structural, dielectric and optical properties of Ta₂O₅-Bi₂O₃-P₂O₅ phosphate glasses

¹ Laboratory of Materials, Nanotechnology, and Environment, Faculty of Sciences, Mohammed V University in Rabat, P.O. Box 1014, Agdal-Rabat, Morocco
² CRMEF, Laboratory of Scientific Research and Educational Innovation, Rabat, Morocco
³ Laboratory of Materials, Energy and Environment, Physics Department, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco

^* e-mail: m.elmoudane@gmail.com

Received: 21 April 2022
Received in final form: 21 May 2022
Accepted: 31 May 2022
Published online: 12 August 2022

Abstract

Glasses with the formula 5Ta₂O₅-xBi₂O₃-(95-x)P₂O₅ for 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 (T_g) increases linearly with bismuth oxide content, from 524 °C for x = 10 mol% to 582 °C for x = 20 mol%. When the amount of Bi₂O₃ in the system increases, the density rises and the molar volume (V_M) decreases. The Infrared spectroscopy shows the presence of BiO₆ and PO₃ structural groups and reveals the depolymerization of the phosphate links by the creation of the Bi–O–P groups. Replacing P₂O₅ by Bi₂O₃ shows that the dielectric constant ɛ_r' and dielectric losses tanδ vary 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.