Electronic Structure and External Electric Field Modulation of Polyethylene/Graphene Interface.

Abstract

Polymer nanocomposites can serve as promising electrostatic shielding materials; however, the underlying physical mechanisms governing the carrier transport properties between nanofillers and polymers remain unclear. Herein, the structural and electronic properties of two polyethylene/graphene (PE/G) interfaces, i.e., type-H and type-A, have been systematically investigated under different electric fields using first principle calculations. The results testify that the bandgaps of 128.6 and 67.8 meV are opened at the Dirac point for type-H and type-A PE/G interfaces, respectively, accompanied by an electron-rich area around the graphene layer, and a hole-rich area around the PE layer. Moreover, the Fermi level shifts towards the valence band maximum (VBM) of the PE layer, forming a p-type Schottky contact at the interface. Upon application of an electric field perpendicular to the PE/G interface, the Schottky contact can be transformed into an Ohmic contact via the tuning of the Schottky barrier height (SBH) of the PE/G interface. Compared with the A-type PE/G interfaces, the H-type requires a lower electric field to induce an Ohmic contact. All these results can provide deeper insights into the conduction mechanism of graphene-based polymer composites as field-shielding materials.