Mechanism of charge transport in poly(2,5-dimethoxyaniline)

Abstract

Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio of oxidants; ferric chloride (FeCl3) and ammonium persulfate [(NH4)2S2O8], in an inert atmosphere at low temperature ∼278 K. The synthesized samples of PDMA have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and by measuring its dc conductivity (σdc). The temperature dependence of dc conductivity of PDMA samples has been examined in the wide temperature range 6–303 K. The analysis of dc conductivity data reveals that in the temperature range ∼100–303 K, the dc conductivity is predominantly governed by Mott’s three-dimensional variable range hopping, however, below 100 K tunneling seems to dominate. Different Mott’s parameters such as characteristic temperature (T0), density of states at the Fermi level [N(EF)], the average hopping distance (R), and the average hopping energy (W) have been estimated for all the PDMA samples and are in good agreement with the values reported earlier for other conjugated polymers.