Enhancement in optical, thermal and electrical properties of Polyvinyl pyrrolidone/ polyethylene oxide matrix-based nanocomposites for advanced flexible optoelectronic technologies considering nanoceramic zinc oxide/titanium dioxide filler

Abstract

Polyvinyl pyrrolidone (PVP) and polyethylene oxide (PEO) hybrid nanocomposites with varying zinc oxide (ZnO) and titanium dioxide (TiO2) concentrations were created using the solution casting process. The influence of ZnO/TiO2 nanoparticles on the optical, thermal, and electrical properties of the pure PVP/PEO composite was investigated and discussed. The results of the XRD analysis show that as ZnO/TiO2 NPs concentrations increases, the crystallinity of the nanocomposite films decreases. The interactions between the ZnO/TiO2 nanoparticles and the PVP/PEO polymeric chain is shown by FT-IR spectra. Peak positions and intensity variations in the FT-IR absorption spectra are observed when the concentration increases from 0.5 to 2 wt.% of ZnO/TiO2 NPs. The optical parameters including energy gap (Eg), refractive index (n), and Urbach energy (Eu) for PVP/PEO/ZnO/TiO2 nanohybrid samples were calculated using UV/Vis analytical spectroscopy. The energy gap narrows when ZnO/TiO2 nanohybrid concentration rises, as shown by the optical absorption spectra. The allowed indirect energy gap of the polymer matrix was reduced from 3.72 to 1.94 eV by the addition of 2 wt.% ZnO/TiO2 NPs. The TGA curve shows that the ZnO/TiO2 nanohybrid enhanced the thermal stability of the samples. As the concentration of metal oxides increased, the activation energy (Ea) decreased. AC conductivity showed that the PVP/PEO -(2 wt.%) ZnO/TiO2 NPs nanocomposites have higher electrical conductivity than PVP/PEO. For samples of -(2 wt.%) ZnO/TiO2, the σdcof nanocomposites reached 4.64×10−5Scm−1. Exponential factor (S) results show that in nanocomposite samples with non-Debye relaxation processes, the correlated barrier hopping mechanism (CBH) is dominant. High values of ε' at low-frequency in the dielectric characteristics demonstrated space charge polarization, whereas higher values of ε" in the composite samples could be associated with an increase in energy loss. These results illustrate the appropriateness of these nanocomposites for variety of uses, including flexible capacitors, battery separators, and energy storage devices.