Reinforced PEO/Cs polymers blend with Al2O3/TiO2 hybrid nanofillers: Nanocomposites for optoelectronics and energy storage

This work focuses on the meticulous preparation and characterization of polyethylene oxide (PEO)/chitosan (Cs) polymer blends infused with aluminum oxide nanoparticles (Al2O3 NPs) and sol-gel synthesized titanium oxide nanoparticles (TiO2 NPs). Employing the casting method, the study delves into a comprehensive analysis of the structural, optical, electrical, and dielectric properties exhibited by the resulting PEO/Cs-Al2O3/TiO2 nanocomposites. Structural evaluations utilized transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). UV–Vis spectra showed enhanced optical properties, with the indirect optical energy gap decreasing from 5.23 eV to 5.01 eV for blends with 2.4 wt% Al2O3/TiO2 NPs. The AC conductivity of the polymeric nanocomposites showed enhanced values compared with the pure blend. Additionally, dielectric permittivity and modulus exhibit tunability, presenting advantageous prospects with varying Al2O3/TiO2 NPs concentrations in the PEO/Cs blend. The Nyquist plots reveal distinctive features, including semicircular arcs at the low-frequency part and an inclined spike at the high-frequency part, with decreasing arc radius corresponding to increasing nanofiller contents. These observations are best fitted to two models of equivalent circuits. The engineered PEO/Cs-Al2O3/TiO2 nanocomposite capacitor showed enhanced storage capacity and controlled conductance characteristics. The findings of this study revealed that these nanocomposites hold promise as bandgap tuners, optical sensors, permittivity-tunable nanodielectrics, and novel host matrices for the development of solid polymer flexible electrolytes, thereby contributing to the next generation of energy storage and conversion devices with superior performance.