Poole-Frenkel emission on functionalized, multilayered-packed reduced graphene oxide nanoplatelets

Abstract

The unique electronic, mechanical and optical properties of graphene make it a remarkable 2D material, widely explored in a plethora of applications. However, graphene zero-bandgap and the production of defect-free pristine graphene in large areas still limit some applications. To circumvent these issues, graphene-derived 2D materials have arisen as attractive candidates for low-dimensional systems, which requires a better comprehension of their properties. Here, we report a detailed investigation of the conduction mechanisms of two functionalized reduced graphene oxides (rGOs) nanoplatelets, named GPAH and GPSS. The functionalized rGO nanoplatelets were bottom-up assembled via the layer-by-layer technique, enabling molecular-level thickness control of nanostructures with well-defined composition and structure. For the reported multilayered GPAH/GPSS films the charge carriers followed Mott's law, presenting a typical conduction behavior of 2D systems described by the Poole-Frenkel model. The multilayered GPAH/GPSS nanostructure presented a conductivity of 10-4 S cm-1, optical bandgap of ∼3.3 eV and a relative dielectric permittivity (ϵ r) of 6.4. Temperature-dependent I-V measurements indicated a strong variation of ϵ r below the critical temperature (T C = 237 K), associated with a high dipole reorientation in the formed GPAH/GPSS nanostructure. All these characteristics make the GPAH/GPSS nanocomposite attractive for graphene-oriented applications, such as electronic devices.