Investigation of three-dimensional Mott’s VRH conduction mechanism in core–shell structured polyaniline/zinc oxide nanocomposites for sensing applications

Abstract

The electrical conductivity in polyaniline/zinc oxide (PANI/ZnO) nanocomposites possess core–shell structures has been reported in present research work and Mott’s variable range hopping (VRH) conduction mechanism to explain the reason behind increased conductivity. The core–shell structured pristine and ZnO nanoparticles (NPs) embedded polyaniline nanocomposite samples have been synthesized through chemical oxidative polymerization synthesis route with different doping concentrations of ZnO NPs, i.e., 0, 5, 10, 15, and 20 wt% in polyaniline (PANI) matrix. The formation of desired samples has been inveterate through Fourier transform infrared spectra (FTIR) which show the existence of required various fundamental bands in the samples. The enhancement in ratio of area under the curves of bipolaronic to polaronic band from 1.2742 to 1.5496 with the enhancement in ZnO NPs concentration in the PANI matrix indicates an increase in electrical conductivity. The prepared samples have electrical conductivity in semi-conducting range, i.e., 0.28 × 10^–4, 1.01 × 10^–4, 2.22 × 10^–4, 4.96 × 10^–4 and 6.29 × 10^–4 S/cm for the samples Z0, Z1, Z2, Z3 and Z4, respectively. This observed enhancement in electrical conductivity with the increase in operating temperature suggests the semi-conducting nature of prepared samples. Due to the constraints of the Arrhenius and Kivelson model, the charge transport properties were investigated systematically through Mott’s variable range hopping (VRH) model. In the given temperature range, the electrical conductivity of all the pristine and nanocomposite is well followed with a three-dimensional VRH model. In addition, results suggest that the material can be beneficial in their utilization as sensing applications.