An insight into the influence of CuO NPs on the structural, dielectric, optical, and conductivity properties of PEO/PVA-CuO nanocomposite for energy storage nanoelectronic devices

In this work, the synthesis of copper oxide nanoparticles (CuO NPs)-polyvinyl alcohol (PVA)/polyethylene oxide (PEO) nanocomposite films was fabricated via the solution casting technique. An X-ray diffraction (XRD) study demonstrated a significant reduction in the crystallinity of the PEO/PVA-CuO nanocomposites with increasing nanoparticle content. Fourier-transform infrared spectroscopy (FTIR) confirmed a strong interaction between the PEO/PVA blend and the CuO NPs. UV-Vis spectrophotometry was employed to determine the direct and indirect optical bandgaps using Tauc plots. The finding showed that when the concentration of nanoparticles increased, the indirect and direct bandgaps decreased. Specifically, the direct bandgap reduced from 5.33 eV to 3.79 eV, and the indirect bandgap reduced from 5.09 eV to 3.01 eV as the nanoparticle concentration increased from 0 to 1.3wt%. Furthermore, an increase in nanoparticle content led to an increasing in Urbach energy. The dielectric loss, AC conductivity, and dielectric constant of the nanocomposite films were significantly higher than those of the PEO/PVA blend, and these properties exhibited a further increase with higher nanoparticle loadings. The conductivity and dielectric properties of the PNCs reached a maximum at a nanoparticle concentration of 1.3wt%. Notably, the conductivity of the nanocomposites increased by nearly 5 times when the CuO content was increased to 1.3wt%. Overall, compared to the pure PEO/PVA blend, the polymer nanocomposites demonstrated superior dielectric, optical, and electrical properties, making them promising candidates for optoelectronic applications and the fabrication of high-energy storage nanoelectronic devices.