Effect of heavy metal oxide and alkaline earth oxide on optical, and electrical properties of tellurite-phosphate glass composites

In the present report, the combined effects of the incorporation of Bi 2 O 3 and BaO into the host glassy network of chemical formula x Bi 2 O 3 -(0.4- x ) BaO-0.25TeO 2 -0.35P 2 O 5 ( x = 0, 0.05, 0.15, and 0.20) are studied. The X-ray diffraction reveals some nanophases like Ba 3 Te 2 O 9 , BaTeO 3 , Ba 3 Te 4 O 11 , BaTeO 3 , Ba 2 P 2 O 7 , Ba 3 (PO 4 ) 2 , Ba 3 (PO 4 ) 2 , BaO 2 are superimposed within the synthesized glassy matrices. The SEM images reveal fine crystallite particles are dispersed randomly throughout the matrix in a localized colony -like arrangement, and EDX spectra indicate the weight and atomic percentage of each constituent element. Analysis of Raman spectra confirms various band formations. Density, molar volume and other physical properties have been correlated with structural modifications. Tauc ' s plot confirms the decrement in optical band gap energies from 3.91 eV to 3.40 eV, conversely, the Urbach energy values increase from 0.53 eV to 0.69 eV. The absorption coefficient, extinction coefficient, and refractive index have been examined and interpreted accordingly. The well-known Wemple Di Domenico (WDD) model has been deployed to analyse the dispersive parameters. The Almond - West formalism is used to study the electrical conductivity of all glass nanocomposite samples. The modified correlated barrier -hopping (CBH) model explains the AC conductivity mechanism. The semiconducting non-linear characteristic is conspicuously observed from the DC conductivity spectra.