Elastic moduli, optical and electrical properties of mixed electronic-ionic 30Li2O-4MoO3-(66-x)TeO2-xV2O5 tellurite glass system

Abstract

The melt-quenching technique was applied to prepare mixed electronic-ionic 30Li2O-4MoO3-(66-x)TeO2-xV2O5 tellurite glasses in order to assess their DC conductivity, as well as their optical and elastic properties. As a result, initial weak increase was noted in DC conductivity for x ≤ 0.6 V2O5 prior to a sharp decline for x = 0.8 mol% and massive increment for x > 0.8 mol%. Non-linear features were displayed by elastic modulus, shear modulus (µ), and independent longitudinal modulus (CL) as the values were minimised to x = 0.8 mol% prior to increment at x > 0.8 mol% upon adding V2O5. The elastic modulus that reduced at x ≤ 0.8 mol% indicated a decrease in rigidity and stiffness of the glasses, mainly because of increment in non-bridging oxygen (NBO) that weakened the network of the glasses due to MoO3 and TeO3. This was followed by massive increase when x exceeded 0.8 mol% due to increment in bridging oxyegen (BO) that was contributed by VO5 with the formation of strong covalent V-O bond. Meanwhile, the anomalous condition recorded when x = 0.8 mol% was due to mixed ionic-electronic (MIE) effect, which appeared to coincide with DC conductivity. Within the similar area, refractive index (n) and optical band gap (Eopt) displayed off-trend pattern that signified polarizability difference led by alteration in BO and NBO concentrations. These findings were supplement to previous work on AC conductivity and dielectric properties of the same glass system by the authors.