Nanoengineered Nickel/reduced graphene oxide composites: control of interfacial nanostructure for tunable electrophysical properties

Abstract

Here we present a novel solvothermal synthesis approach for the accurate control over the structural features of nickel/reduced graphene oxide (Ni/rGO) nanocomposites for tuneable electrical properties. We discovered that the dynamic chemical structure of GO during reaction, acts as an active template for the controlled nanostructured growth of nickel nanoparticles (Ni NPs). Therefore, the precise control of reaction time offered the possibility to modulate nucleation and coalescence phenomena of Ni NPs, allowing in this way to precisely adjust their size, density and NiO@Ni structure on the final Ni/rGO nanocomposites. The electrophysical properties (work function and conductivity) of different Ni/rGO nanocomposites were determined and found to be directly dependent on the Ni NPs radius and also on the NiO buffer layer width. We confirmed a crucial role of the NiO buffer layer thickness at the Pt-NiO-Ni-NiO-rGO interface changing the conductivity from metallic to those specific to a Schottky contact or to a p-n heterojunction. These new findings reveal a relevant potential for using Ni/rGO nanocomposites as a versatile and promising material for micro-, nano- and optoelectronics as well as for energy storage technologies.