Polypyrrole decorated graphene nanostructure: Fabrication, depiction and anomalous dimensional crossover in electronic conduction

Abstract

We had fabricated polypyrrole based graphene nanostructure by using CTAB (cetyl trimethylammonium bromide) surfactant with variation of graphene loading and characterized them by XRD, FT-IR, SEM, TEM, AFM, Raman etc. Variable range hopping (VRH) model had been applied for explication of temperature dependent D.C. conductivity scrutinized from 20 to 300K. A synergetic effect of π-electron flow in conducting polymer polypyrrole and 2D graphene layer was appeared to demonstrate the plausible charge-transport mechanism. Dramatically, two peculiar crossovers had been observed simultaneously in the composite samples with variation of temperature. A 3D–2D effective dimensional crossover had been observed at ≈100K with variation of hopping length which can be controlled by temperatures. Below ≈50K another cross-over between Mott and ES (Efrost & Shklovskii) type VRH mechanism had also been explored as resistivity increases with lowering of temperature. Here, charge transport occurred via VRH between intact graphene island and polypyrrole chain.