Low temperature double transition charge transport mechanism in co-doped polyaniline nanocomposites

In this study, low temperature electrical conductivity of pristine polyaniline and polyaniline/activated charcoal nanocomposites with four different loading concentrations of activated charcoal (2, 4, 6, and 8 wt%) synthesized through chemical oxidative polymerization method is presented. Surface analysis of the prepared nanocomposites was done using Field emission scanning electron microscope. The energy band for pristine are found to be 2.68 eV whereas it is decreases up to 2.41 eV after introducing 8 wt% loading concentration of AC. The Pristine PANI sample contains the high value of electrical conductivity i.e. 32.34 S/cm which increases upto 168.87 S/cm with the 8 wt% loading of activated charcoal in PANI matrix which is also evident with the increase in A_Q/A_B ratio from 0.214 to 0.408 using FTIR. The Mott’s VRH model was found to be in agreement to explain the conduction mechanism in these samples. The Debye temperature for one-dimensional to two-dimensional hopping are found to be ~ 15, 18, 19, 22, 25 K whereas Debye temperature for two-dimensional to three-dimensional hopping are found to be ~ 28, 34, 36, 44, 46 for S0, S1, S2, S3, S4 samples, respectively. The enhancement in density of states from 3.05 × 10¹⁹ to 30.99 × 10¹⁹ eV⁻¹ cm⁻³ and decrease in hopping distance from 341.59 to 191.38 nm in high tempreature region with the increase of loading concentrations of activated charcoal indicates the requirement of lesser hopping energy for charge transport.