Dielectric Relaxation Behavior and Electrical Conduction Mechanism of PVA/ZnO Nanocomposites for Flexible Electronic Device Application

Abstract

Transport properties of polyvinyl alcohol/ZnO nanocomposites (PVA/ZnO) of varying ZnO nanofiller are studied focussing on their potential application in electronic device application. The structural, morphological, and elemental composition studies of the prepared samples are done by X‐ray diffraction (XRD), scanning electron microscope (SEM), and energy‐dispersive X‐ray analysis (EDX). XRD confirms the formation of nanocomposites. SEM image shows the dispersion of ZnO nanoparticles on the surface of PVA matrix. EDX verifies that no external impurities are present in the nanocomposite samples. Frequency‐ and temperature‐dependent dielectric measurement of the samples reveals maximum dielectric constant at PVA/15 wt% ZnO nanocomposite. Dielectric loss results show a lossless behavior at higher frequencies (<0.2), indicating their suitability for high‐frequency applications. The AC conductivity studies reveal that electrical conduction mechanism in the nanocomposites is governed by the correlated barrier hopping mechanism. Activation energy of the samples reveals the presence of two thermally activated transport mechanism above and below 353 K. The imaginary part of electric modulus with frequency shows a single relaxation peak indicating the transition from long‐range to short‐range mobility with increasing frequency and temperature above 353 K. The contribution of grain and grain boundary in the electrical conduction process is confirmed from the Nyquist plot.