Enhanced structural, optical, dielectric, and electrical properties in polymer nanocomposite films via loading AgNO₃ NPs for emerging optical and electrical applications

This work explores the development and properties of novel nanocomposite materials. The nanocomposites were synthesized using a casting method and comprised blends of polyvinyl alcohol (PVA) and sodium alginate (NaAlg) with varying concentrations of silver nitrate nanoparticles (AgNO₃ NPs). XRD analysis revealed an increasing trend in the amorphous character of the PVA/NaAlg blends with the addition of AgNO₃ NPs. This suggests improved dispersion of the nanoparticles within the polymer matrix. FTIR results indicated the formation of potential molecular interactions between the polymer chains and the AgNO₃ nanofillers, potentially influencing the overall material properties. UV–Vis spectroscopy, along with Tauc’s relation, was used to determine the direct and indirect bandgap energies of the nanocomposites. Notably, the addition of 7 wt% AgNO₃ NPs led to a significant decrease in the direct bandgap energy (E_g) of the pristine PVA/NaAlg blend, from 5.03 eV to 4.69 eV. This reduction suggests improved light absorption potential within the nanocomposite. The dielectric behavior and electrical conductivity of the nanocomposite films were also investigated. Interestingly, the dielectric constant and dielectric loss exhibited an opposite trend compared to the AC conductivity. While AC conductivity increased with frequency, the dielectric constant and loss decreased. However, the study revealed a positive correlation between AgNO₃ concentration and the dielectric loss and constant values, indicating an influence of AgNO₃ content on the dielectric response. The fabricated PVA/NaAlg-AgNO₃ nanocomposite films exhibit promising properties, including improved AC conductivity and dielectric characteristics. These findings suggest their potential application in various technological fields, such as optoelectronic devices and electrical applications.