Enhancement of dielectric properties by modulating electroactive β-phase of copper doped nickel oxide nanoparticles incorporated thin film

Polymer nanocomposites (PNCs), exhibiting enhanced physical properties, are emerging as innovative functional materials due to their versatile characteristics suitable for various technological applications. Composite films comprising 0.1% copper (Cu) doped Nickel oxide (NiO) [CNO1 (350)] nanoflakes calcined at 350 °C embedded in Poly (vinylidene fluoride) (PVDF) polymer were prepared using the solution casting method. The influence of CNO1 (350) filler incorporation on the structure and morphology of the composite films was scrutinized through X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FESEM). Results unveiled a direct correlation between CNO1 (350) filler concentration and the crystallinity, β-phase content, and morphology of the composite films, attributed to heterogeneous nucleation. Room temperature electrical measurements indicated dielectric constants reaching more than six times at 40 Hz and a conductivity increase exceeding two orders of magnitude, with a percolation threshold identified around 25wt% of CNO1 (350) filler content. The observed outcomes are elucidated through Maxwell–Wagner–Sillars interfacial polarization occurring at the interface of CNO1 (350) and the insulating polymer matrix. This elucidation involves the development of a conductive network and the establishment of a micro-capacitive structure within the PVDF thin films modified with CNO1 (350).