Variable Range Hopping (VRH) charge transport and Poole-Frenkel type conduction mechanism of polypyrrole synthesized with Chemical Oxidative Polymerization

Abstract

Polypyrrole (PPy) was prepared with various weight loadings of acetic acid (10, 30 and 50 wt.%) over chemical oxidative polymerization. The structural and electrical properties of the prepared samples were characterized by XRD and electrical analysis. The charge transport mechanism of PPy was executed by Keithley (6517B) equipment performed between a voltage of 1 to 10 V by the increment of 1 V. The current over capacitor as a role of the applied voltage was carried out from 303 to 403 K temperature range. The XRD result confirms the amorphous nature of PPy. The charge transport process of PPy was deliberated by Mott’s variable-range hopping (VRH) through the conductivities and they found using various weight loadings of acetic acid. The conductivity (σdc) was found to increase with the temperature increase, which indicates the semiconducting nature and the conductivity value calculated was 10− 9 to 10− 7 S/cm for various weight loadings of acetic acid. The I-V study outcomes the linear behavior and the semiconducting nature of PPy, and the study was completed by the explanation of the Poole-Frenkel type conduction mechanism, ln (J) vs. T plots in PPy samples at high fields. It concludes that the comparison of theoretical field-lowering coefficients βS and βPF and the experimental field-lowering coefficients βS and βPF were correlated and the result confirms the Poole-Frenkel type conduction mechanism in PPy. The activation energy diminishes from 1.22 to 1.07 eV with an increase of acetic acid weight percentage.