Boosting of Structural, Optical, and Dielectric Characteristics of PVA Polymer Using CoO-SiO₂ Nanoparticles for Advanced Optoelectronic Applications

The goal of this research is to improve the silicon dioxide (SiO₂), cobalt oxide (CoO), and polyvinyl alcohol (PVA) nanostructures' structural, optical, and dielectric properties. The casting method with varied concentrations of CoO-SiO₂ NPs (0, 2, 4, and 6 wt.%) was used to create PVA-CoO-SiO₂ NCs. Structural, optical, and electrical characteristics were investigated. Using optical microscopy, it was discovered that the CoO-SiO₂ NPs form a coherent network inside the polymer matrix, in contrast to the pure PVA film. FTIR analysis shows no chemical interaction between polymer and nanoparticles. Experimental results of the optical properties of PVA-CoO-SiO₂ nanocomposites revealed that the absorption, absorption coefficient, refractive index, extinction coefficient, the real and imaginary part of dielectric constant, and optical conductivity of PVA increased with increasing concentrations of CoO-SiO₂ NPs, whereas the transmittance and energy gap (allowed and forbidden) decrease. The optical energy gap of indirect transitions (allowed and prohibited) decreased from 4.37 eV to 1.74 eV and from 4 eV to 1.2 eV, respectively, and these results may be key to using the PVA-CoO-SiO₂ nanostructures in different photonics fields and optoelectronics nanodevices. The alternating current electrical properties of nanocomposites reveal that when the frequency of the applied electric field increases, the dielectric constant and dielectric loss decrease, while AC electrical conductivity increases. On the other hand, the dielectric properties of nanocomposites increased as the concentration of CoO-SiO₂ NPs increased. The study's findings imply that including CoO-SiO₂ nanoparticles in the PVA doping process improved structural, optical, and electrical characteristics, making the PVA-CoO-SiO₂ NCs suitable materials for different optoelectronic nanodevices.