1 Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, China 2 Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 3 Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, China
These authors contributed equally to this work.
Keywords:Graphene, solvothermal-assisted exfoliation, monolayer and bilayer, high quality
Monolayer and bilayer graphene sheets have been produced by a solvothermal-assisted exfoliation process in a
highly polar organic solvent, acetonitrile, using expanded graphite (EG) as the starting material. It is proposed
that the dipole-induced dipole interactions between graphene and acetonitrile facilitate the exfoliation and
dispersion of graphene. The facile and effective solvothermal-assisted exfoliation process raises the low yield of
graphene reported in previous syntheses to 10 wt% 12 wt%. By means of centrifugation at 2000 rpm for 90 min,
monolayer and bilayer graphene were separated effectively without the need to add a stabilizer or modifi er.
Electron diffraction and Raman spectroscopy indicate that the resulting graphene sheets are high quality
products without any signifi cant structural defects.