Frequency Dependent Energy Gap and Polarization Effects in ZnO Doped Polypyrrole

The frequency-dependent energy gap and polarization effects in ZnO-doped Polypyrrole (PPy) nanocomposites with ZnO loadings of 4% and 5% were investigated exclusively under polarised conditions. Temperature-dependent electrical behaviour was examined using Arrhenius-type plots of the natural logarithm of resistance (LnR) versus inverse temperature (1/T) over a frequency range of 100–5000 Hz. The apparent activation energy and effective energy gap were evaluated to understand polarisation-assisted charge transport mechanisms. Both compositions exhibit thermally activated conduction characteristic of semiconducting behaviour, with effective energy gap values lying in the range of approximately 0.62–0.99 eV. Polarisation leads to a reduction in the effective energy gap, attributed to dipole alignment, enhanced polaron formation and improved hopping pathways for charge carriers. The 4% ZnO doped PPy nanocomposite shows a comparatively lower energy gap than the 5% ZnO sample, indicating more efficient interfacial polarisation and stronger polymer nanofiller interactions at this concentration. Frequency-dependent behaviour suggests that interfacial and dipolar polarisation mechanisms dominate at lower frequencies, while higher frequencies restrict carrier response, resulting in minor variations in the energy gap. Deviations from ideal Arrhenius linearity imply non-Arrhenius conduction involving hopping transport, trap-assisted mechanisms and structural disorder. The results highlight the significant role of polarisation and ZnO concentration in tailoring the electronic structure and charge transport properties of ZnO/PPy nanocomposites for advanced dielectric and electronic applications.