Improving the conductivity of PEDOT:PSS to nearly 1 million S/m with graphene on an ITO-glass substrate

Abstract

In this study, we effectively improved the electrical conductivity of poly(ethylene-3,4-dioxythiophene):poly (styrenesulphonic acid) (PEDOT:PSS) thin film by introducing various concentrations of our highly conductive synthesized graphene. The electrical conductivity of the PEDOT:PSS was enhanced from 597418.17 to 899076.24 S/m when a 2 mg/ml concentration of graphene was added to the PEDOT:PSS. However, the addition of graphene in excess (2.5 mg/ml) decreased the conductivity to 719130.49 S/m, which might have been because of further defects being generated in the film that obstructed the fast transport of charge carriers to the current probes of the four-point probe. X-ray diffraction pattern, Raman spectroscopy and X-ray photoelectron spectroscopy analyses suggest that the graphene-PEDOT:PSS composite contained various kinds of chemical functionalizations that provided an additional pathway in the form of cross-linking bridges for the very quick transport of free charge carriers from the voltage probe to the current probe, resulting in enhanced carrier mobility.