Examination of the structural, morphological, and optical band gap of PVP incorporated with V2O5 nanofiller

Abstract Polyvinylpyrrolidone (PVP): V₂O₅ nanocomposite films were successfully fabricated using a simple solution casting technique to enhance the structural and optoelectronic properties of the polymer matrix. An X-ray diffraction structural analysis reveals that pure PVP is mostly amorphous; however, the incorporation of V₂O₅ nanoparticles yields orthorhombic crystalline reflections, suggesting a significant interaction between the polymer chains and the nanoparticles. FTIR analysis demonstrates that the carbonyl groups of PVP and V–O linkages were able to work together, which kept the polymer backbone intact. Field emission scanning electron microscopy showed that nanoparticles were evenly spread out at low filler concentrations and that there was not much agglomeration at higher loadings. The UV–visible spectroscopy study was carried out to measure the fundamental optical parameters, including absorption edge, refractive index (n), band gap energy (Eg), impedance, extinction coefficient (k), sheet resistance (Rs), and thermal emissivity (εTh) of the pure PVP and nanocomposite films. The results showed the move of the absorption edge to red shift and a substantial decrease in the optical band gap, decreasing from 4.79 eV for pure PVP to 2.05 eV for the nanocomposite films. Moreover, the refractive index, dielectric constant, and optical polarizability increased with increasing V₂O₅ concentration, whereas Urbach energy, sheet resistance, and optical impedance dropped, indicating enhanced electronic polarization and charge transfer. The Wemple-DiDomenico (WDD) model was used to calculate the Ed, Eo, and n₀ parameters. The value of Eo obtained from the WDD model closely matches the optical energy band gap obtained from the Tauc model, which indicates the precision of the analysis in the present study. The findings demonstrate that the controlled incorporation of V₂O₅ nanoparticles significantly alters the optoelectronic characteristics of PVP films, presenting a feasible strategy for the enhancement of flexible optoelectronic and photonic materials with prospective applications in solar cells, energy devices, organic light-emitting diodes (LEDs), and optical adhesives.