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

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.