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.
LCN 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. 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.
Journal link: Structure and Morphology of Charged Graphene Platelets in Solution by Small-Angle Neutron Scattering, J. Am. Chem. Soc., 2012, 134 (20), pp 8302–8305. DOI: 10.1021/ja211869u http://pubs.acs.org/doi/abs/10.1021/ja211869u
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