Graphene production

Najafabadi, A. T, and Gyenge, E. (2014]. High-yield graphene production by electrochemical exfoliation of graphite Novel ionic... 

Knieke C, Berger A, Peukert W (2010) Graphene production with stirred media mills. MRS Proc 1259 1259-512-01. doi 10.1557/PROC-1259-S12-01... 

From the above discussion, it is evident that the graphene morphology and its properties depend strongly on the synthesis method. Before discussion the electrochemical related aspects of graphene, the technological advances of graphene production will be presented. 

The quantity x is a dimensionless quantity which is conventionally restricted to a range of —-ir < x < tt, a central Brillouin zone. For the case yj = 0 (i.e., S a pure translation), x corresponds to a normalized quasimomentum for a system with one-dimensional translational periodicity (i.e., x s kh, where k is the traditional wavevector from Bloch s theorem in solid-state band-structure theory). In the previous analysis of helical symmetry, with H the lattice vector in the graphene sheet defining the helical symmetry generator, X in the graphene model corresponds similarly to the product x = k-H where k is the two-dimensional quasimomentum vector of graphene. 

MWCNT synthesized by catalytic decomposition of hydrocarbon does not contain nanoparticle nor amorphous carbon and hence this method is suitable for mass production. The shape of MWCNT thus produced, however, is not straight more often than that synthesized by arc-discharge method. This differenee could be aseribed to the strueture without pentagons nor heptagons in graphene sheet of the MWCNT synthesized by the catalytic decomposition of hydrocarbon, which would affect its electric conductivity and electron emission. 

The combination of low optical absorbance and high electrical conductivity has attracted a lot of interest for transparent conductor applications. When coupled with its flexibility, it is widely seen as a possible replacement for indium-doped tin oxide (ITO), which has a sheet resistance of 100 Q/cm at 90 % transparency. By growing graphene on copper foils, sheet resistances of 125 Q/cm at 97.4% transparency have been achieved [19]. This has been improved by combining four layers with doping of the graphene, giving resistance of 30 Q/cm at 90% transparency, all done on 30-inch roll-to-roll production scale. 

In contrast, exfoliation of graphene in liquid environments offers a route to large-scale production, from simple starting materials. There are various approaches that have been developed to enable effective exfoliation of graphene in liquids. 

Y. Hernandez, V. Nicolosi, M. Lotya, F.M. Blighe, Z. Sun, S. De, et ah, High-yield production of graphene by liquid-phase exfoliation of graphite, Nature Nanotechnology, 3 (2008) 563-568. 

M. hotya, Y. Hernandez, P.J. King, R.J. Smith, V. Nicolosi, h.S. Karlsson, et ah, hiquid phase production of graphene by exfoliation of graphite in surfactant/water solutions, Journal of the American Chemical Society, 131 (2009) 3611-3620. 

A.A. Green, M.C. Hersam, Solution phase production of graphene with controlled thickness via density differentiation, Nano Fetters, 9 (2009) 4031-4036. 

C. Soldano, A. Mahmood, E. Dujardin, Production, properties and potential of graphene, Carbon, 48 (2010) 2127-2150. 

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