Effect of vanadium pentoxide on the electrical, dielectric, and optical properties of poly(vinyl alcohol)/vanadium pentoxide nanocomposites

Abstract

In this study, the effect of vanadium pentoxide (V2O5) on the electrical, dielectric, and optical properties of poly(vinyl alcohol) (PVA)/V2O5 nanocomposites was examined. The PVA/V2O5 nanocomposites were prepared by solution mixing, followed by film casting. The as-prepared films were characterized by X-ray diffraction, thermogravimetric analysis, as well as impedance spectroscopy. The obtained results indicated that, with increasing V2O5 content, the PVA composite exhibits considerable vestige of crystallization and the PVA peaks become broader. The electrical conductivity, σ dc, increases as the temperature and the dopant level of V2O5 increase. The frequency dependence of alternating current conductivity was governed by a critical frequency, ω p. The values of ω p are found to be thermally activated. The loss tangent (tan δ) shows a peak with the frequency, which indicates a dielectric relaxation in these composites with relaxation time decreases with both temperature and V2O5 content increase. Optical absorption edge and direct and indirect energies for all mentioned samples were determined and discussed.