High yield production of graphene by liquid phase exfoliation of graphite

TL;DR

This paper presents a scalable liquid phase exfoliation method to produce high-yield, defect-free graphene dispersions in organic solvents, enabling large-scale applications in electronics and chemistry.

Contribution

It demonstrates a cost-effective, high-yield process for producing high-quality graphene dispersions via liquid phase exfoliation in matching surface energy solvents.

Findings

Graphene dispersions with concentrations up to 0.01 mg/ml.

Yields of up to 12% by mass of graphene.

Produced graphene is defect-free and suitable for conductive films.

Abstract

Graphene is at the centre of nanotechnology research. In order to fully exploit its outstanding properties, a mass production method is necessary. Two main routes are possible: large-scale growth or large-scale exfoliation. Here, we demonstrate graphene dispersions with concentrations up to ~0.01 mg/ml by dispersion and exfoliation of graphite in organic solvents such as N-methyl-pyrrolidone. This occurs because the energy required to exfoliate graphene is balanced by the solvent-graphene interaction for solvents whose surface energy matches that of graphene. We confirm the presence of individual graphene sheets with yields of up to 12% by mass, using absorption spectroscopy, transmission electron microscopy and electron diffraction. The absence of defects or oxides is confirmed by X-ray photoelectron, infra-red and Raman spectroscopies. We can produce conductive, semi-transparent films and conductive composites. Solution processing of graphene opens up a whole range of potential large-scale applications from device or sensor fabrication to liquid phase chemistry.