Graphene electrical conductivity

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. 

I. Jung, D. A. Dikin, R. D. Piner, R. S. Ruoff, Tunable electrical conductivity of individual graphene oxide sheets reduced at low temperatures, Nano Lett., vol. 8, pp. 4283-4287,... 

Fig. 6.7 (a) The variation of electrical conductivity of PVA-EG hybrid with increasing graphene content. Inset shows the dependence of dielectric constant for the hybrid, (b) The variation of conductivity of the polystyrene-graphene hybrid with filler content. Inset shows the four probe setup for in-plane and transverse measurements and the computed distributions of the current density for in-plane condition (reference [8]). 

Pang FI, Chen T, Zhang G, Zeng B, Li Z-M. An electrically conducting polymer/graphene composite with a very low percolation threshold. Materials Letters. 2010 Oct 31 64(20) 2226-9. 

Figure 6.48. Illustration of the honeycomb 2D graphene network, with possible unit cell vector indices n,m). The dotted lines indicate the chirality range of tubules, from 0 = 0 (zigzag) to = 30° (armchair). For 0 values between 0 and 30°, the formed tubules are designated as chiral SWNTs. The electrical conductivities (metallic or semiconducting) are also indicated for each chiral vector. The number appearing below some of the vector indices are the number of distinct caps that may be joined to the n,m) SWNT. Also shown is an example of how a (5,2) SWNT is formed. The vectors AB and A B which are perpendicular to the chiral vector (AA are superimposed by folding the graphene sheet. Hence, the diameter of the SWNT becomes the distance between AB and A B axes. Reprinted from Dresselhaus, M. S. Dresselhaus, G. Eklund, R C. Science ofFullerenes and Carbon Nanotubes. Copyright 1996, with permission from Elsevier.

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