May 28, 2012

Researchers develop a scalable method to produce improved yields of single-layer graphene

(Nanowerk News) Graphene is a remarkable 2-dimensional material that is just one carbon atom thick, providing free-standing atomic crystals with extraordinary physical properties. For example graphene is many times stronger than steel, a better conductor of heat and electricity than copper, and is almost transparent to light. Graphene therefore has numerous potential applications, from ultra-thin displays and touch screens, to transistors and solar panels. However, such applications remain to be realised because there is currently no way to mass-produce graphene.

London Centre for Nanotechnology researchers have now developed a scalable solution-based method that produces greatly improved yields of single-layer graphene, which can then be deposited onto substrates (see paper in JACS: "Structure and Morphology of Charged Graphene Platelets in Solution by Small-Angle Neutron Scattering").

Figures: (left) In situ small-angle neutron scattering (SANS) from solutions of charged graphene sheets in solution of ammonia and THF. (right) "Core-shell-bulk" model of graphene solvation that provided the best fit to the experimental SANS data

First, bulk nanographite was reversibly charged and expanded in a solution of potassium and ammonia.

Second, this "graphenide" salt was then dissolved in organic solvents such as THF.

The presence of single-layer graphene in solution was confirmed by in situ small-angle neutron scattering conducted at the Institut Laue-Langevin in Grenoble, and was corroborated by atomic force microscopy and Raman spectroscopy.

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