A general way to manipulate electrical conductivity of graphene

Electrical conductivity of graphene is one of the most important factors to dominate its applications, which is much lower than conventional good conductors including cooper in spite of its excellent electron mobility, limited by its low carrier density. In this work, a general way to improve electrical conductivity of graphene is proposed via introducing Cu NPs, which are rich in free electrons, into the well-crystalized laser-induced graphene (LIG). The LIG/Cu composite films, with an average diameter of 10 nm of Cu NPs evenly dispersed, were prepared in a laser induction process. It is worth mentioning that the electrical conductivity of porous graphene composited with Cu NPs is increased up to 0.37 × 107 S m−1, which is 3000 times that of pure LIG. To make clear mechanism of this notable phenomenon, the fine structure of Cu-graphene interface is characterized by X-ray Absorption Fine Structure (XAFS) spectroscopy, based on which, Density Function Theory (DFT) calculations are further adopted to reveal the influence of interface structure on electrical conductivity. It is revealed that Cu NPs with surface oxidation state (Cu2+) are most conducive to forming stable bonds with graphene, which will facilitate the electrons transfer from Cu to graphene. As a result, high carrier density and mobility are simultaneously realized in the graphene film, which finally leads to significant electrical conductivity enhancement. The results are of great significance in manipulating electrical conductivity of graphene with respect to various applications.