The polar solvent effect of transparent conductive films composed of graphene/PEDOT:PSS nanohybrids

Highlight
• The mechanism of the polar solvent addition in the graphene/PEDOT:PSS nanohybrids was proposed.
• The sheet resistance of the nanohybrids was significantly improved by IPA addition.
• The conductivity of the nanohybrids was enhanced by H2SO4 secondary treatment.

Novel transparent conductive films were successfully fabricated by forming graphene/PEDOT:PSS nanohybrids and then spin-coating the mixture onto glass substrates. The mechanism and characterization of graphene nanosheets dispersed at various concentrations of polar solvents (isopropanol, IPA) to improve the conductivity of the nanohybrids are evaluated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), four-point probe sheet resistance measurements, and UV/vis spectroscopy. The results show that the conductivity of the graphene/PEDOT:PSS nanohybrids significantly improves upon addition of 50 wt.% IPA (the optimum conditions). The sheet resistance of the nanohybrids was reduced by ~ 95% from 16.6 kΩ/□ by addition of 0 wt.% IPA to 0.85 kΩ/□ by addition of 50 wt.% IPA, whereas the transparency still remained up to 82%. The conductivity could then be rapidly enhanced (from 0.85 kΩ/□ to 0.64 kΩ/□) by a second treatment of H2SO4, with a concomitant loss of transmittance. The correlations among the roughness, hydrophilicity, conductivity, and transparency also are investigated in detail in this paper. It is anticipated that graphene/PEDOT:PSS nanohybrids can be potentially used in an electronic and biomedical platform, such as biosensors.