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High-yield production of graphene by liquid-phase exfoliation of graphite
YENNY HERNANDEZ1, VALERIA NICOLOSI1, MUSTAFA LOTYA1, FIONA M. BLIGHE1, ZHENYU SUN1,2, SUKANTA DE1,2, I. T. McGOVERN1, BRENDAN HOLLAND1, MICHELE BYRNE3, YURII K. GUNKO2,3, JOHN J. BOLAND2,3, PETER NIRAJ2,3, GEORG DUESBERG2,3, SATHEESH KRISHNAMURTHY2,3, ROBBIE GOODHUE4, JOHN HUTCHISON5, VITTORIO SCARDACI6, ANDREA C. FERRARI6AND JONATHAN N. COLEMAN1,2*
1School of Physics, Trinity College Dublin, Dublin 2, Ireland
2Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
3School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
4Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
5Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
6Engineering Department, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK
These authors contributed equally to this work. *mailto:[email protected]
Web End =e-mail: [email protected]
Published online: 10 August 2008; http://www.nature.com/doifinder/10.1038/nnano.2008.215
Web End =doi:10.1038/nnano.2008.215
Fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. Two main routes are possible: large-scale growth or large-scale exfoliation. Here, we demonstrate graphene dispersions with concentrations up to 0.01 mg ml21, produced by dispersion and exfoliation of graphite in organic solvents such as N-methyl-pyrrolidone. This
is possible because the energy required to exfoliate graphene is balanced by the solventgraphene interaction for solvents whose surface energies match that of graphene. We conrm the presence of individual graphene sheets by Raman spectroscopy, transmission electron microscopy and electron diffraction. Our method results in a monolayer yield of 1 wt%, which could
potentially be improved to 712 wt% with further processing. The absence of defects or oxides is conrmed by X-ray photoelectron, infrared and Raman spectroscopies. We are able to produce semi-transparent conducting lms and conducting composites. Solution processing of graphene opens up a range of potential large-area applications, from device and sensor fabrication to liquid-phase chemistry.
The novel electronic properties of graphene have been well documented1; the charge carriers behave as massless Dirac fermions2, and novel effects such as an ambipolar eld effect3, a room-temperature quantum Hall effect4 and the breakdown of the BornOppenheimer approximation5 have all been observed.A graphene monolayer has also been demonstrated as a transparent electrode in a liquid crystal device6. However, as was the case in the early days...