Effect of graphene-oxide on the microstructure and charge carrier transport of polyaniline nanocomposites under low applied electric fields

Abstract

We report a study on the preparation and characterization of polyaniline-graphene oxide (PANI-GO-X) nanocomposites focusing in the study of its structure, microstructure, and correlations with electrical transport properties under low applied electric fields. X-ray diffraction analysis showed evidence of graphene oxide (GO) blending between polyaniline fibers, and according to small angle X-ray scattering, the fractal dimensionality was quasi-one dimensional for all nanocomposites. Confocal Raman spectroscopy revealed that the addition of GO leads to a notorious decrease of the polaron population of polyaniline. A significant increase in resistivity was observed for PANI-GO-X nanocomposites with respect to pure polyaniline, in agreement with the decrease in the polaron population. The electrical transport mechanism could be explained by an Arrhenius behavior at high temperatures (T > 255 K) and a broad transition with a logarithmic dependence of the activation energy with temperature for the low temperature regime (T < 255 K). Additionally, an increase in the hopping transport dimensionality from quasi-1D to quasi-3D was observed for X = 7% GO nanocomposites. The transport properties, studied after the polarization using low applied electric fields, revealed the modification of the electrical transport at low temperatures. In addition, the electrical transport of PANI-GO-X nanocomposites followed a typical ln(σ) vs E1/2 Poole-Frenkel type dependence in the presence of low applied electric fields. At low temperatures, X = 7% GO nanocomposites showed a notorious increase in the Poole-Frenkel slope at low applied electric fields with respect to pure polyaniline. The enhancement on the electric response using low applied electric fields (E ∼ 2 V/cm) could be of great interest for the development of new organic electronic devices.