Conduction Mechanisms in Polypyrrole-Copper Nanocomposites

Abstract

By mixing independently synthesized polypyrole and copper nanoparticles in different proportions, nanocomposites were prepared. Bulk and surface structures were probed by X-ray diffraction and Scanning electron microscopes. DC resistivity with temperature as a variable of all the composites has been investigated. Conductivity has been calculated using resistivity and found it to be of the order 10 – 4 (Ω – 1m – 1), which is greater by one order of magnitude than that reported for polypyrole nanoparticles. Temperature behaviour of conductivity in all the samples revealed semiconducting nature. By applying Mott’s theory of small polaron hopping, activation energy for conductivity at high temperature has been determined. Activation energy is found to be increasing with increase in copper content in the composites. Using data deviated from small polaron model, the density of states at Fermi level is calculated by employing the theory of variable range hopping of polarons due to Mott. It is for the first time that PPy-Cu nanocomposites have been probed for structural and temperature dependence of conductivity and conduction mechanisms operated in these composites in different temperature regions have been understood.