Anisotropic Electrical Transport Properties of Graphene Nanoplatelets/Pyrene Composites by Electric-Field-Assisted Thermal Annealing

Dispersion of graphene nanoplatelets (GNPs) with a pyrene derivative compound (1,3,6,8-tetrakis(4-t-butylphenyl)pyrene (TBPP)) in tetra-hydrofuran as solvent medium is investigated. Field-emission electron microscopy and atomic force microscopy demonstrated the pi-pi stacking interaction between the TBPP compound and the GNPs resulting in the deposition of the TBPP compound onto the exfoliated graphene sheets. We found that the electrical conductivity of the films obtained by the prepared dispersions can be activated in temperature and oriented by the application of an external electric field. We found an increase of the composite conductivity measured along the substrate with respect to the composite conductivity measured perpendicular to the substrate. This result provides an initial understanding of how electric fields can be used to control the bulk physical properties of such composites.