Mechanisms of DC conduction in smart PMN–PT/paint nanocomposite films

Abstract

Understanding conduction mechanisms in dielectric films are critical to their successful applications in devices. DC conduction mechanisms in lead magnesium niobate–lead titanate (0.67Pb (Mg1/3Nb2/3)O3–0.33PbTiO3)/Paint nanocomposite (PMN–PT/Paint) films are presented and discussed. The conventional cost-effective paint brushing technique was utilized to fabricate PMN–PT/paint nanocomposite films on copper substrate. Atomic force microscopy (AFM) has been recognized as one of the most powerful techniques for the analysis of surface morphologies because it creates 3D images at angstrom and nano scale. It has been exhaustively utilized in the analysis of dispersion of nano-metric components in nanocomposites and polymer blends. Thus, AFM analysis is applied in the present work for the surface morphological and dispersion of nanoparticles investigations in paint-based nanocomposites at different loading of PMN–PT nanoparticles. It is found that the PMN–PT nanoparticles are dispersed uniformly inside the paint matrix. The spatial distribution of PMN–PT in PMN–PT/Paint films is denser with higher PMN–PT content sample. A metal–insulator–metal capacitor was fabricated and the leakage current across was measured with varying voltage and temperature. The governing conduction mechanisms were examined and depicted. The activation energy of nanocomposite films fabricated with 2.5 and 8.98 wt% PMN–PT nanoparticles in the paint mixture are found to be 1.08 and 1.24 eV, respectively. The DC activation energy for former was found to be slightly lower then later and follow the Arrhenius relationship. Thus, showing the conduction was electronic and thermally activated.