Engineering dielectric properties and charge transport in PANI/CuO nanocomposites via microstructural control

Abstract

This study systematically investigates the structure-property relationships in polyaniline/copper oxide (PANI/CuO) nanocomposites, with a specific focus on how controlled CuO incorporation (0.5 to 1.25 mol%) tunes their microstructural, dielectric, and charge transport characteristics. The key innovation of this work lies in establishing a direct correlation between CuO-induced lattice expansion and the evolution of charge transport mechanisms, revealing a tunable microstructural-dielectric coupling. X-ray diffraction confirmed successful composite formation, revealing a significant lattice expansion and an optimized microstructure with increased crystallite size and reduced micro-strain. Dielectric spectroscopy demonstrated a remarkable enhancement in the dielectric constant and revealed a distinct interfacial polarization peak. The analysis of AC conductivity identified Overlapping Large-Polaron Tunneling as the dominant charge transport mechanism, a finding further supported by the calculated trends in hopping distance. Complex impedance analysis confirmed non-Debye relaxation behavior and visualized the critical role of interfacial effects, which transition from blocking to conductive with increasing temperature. The PANI/CuO-1 mol composite emerged as the optimal candidate, achieving an ideal balance between high charge storage and efficient transport. This work not only advances the fundamental understanding of charge dynamics in hybrid systems but also underscores the potential of these tailored nanocomposites for high-performance capacitive and optoelectronic applications.