Electrical Conductivity of Graphene

The mobility is theoretically limited to t = 200,000 V s by acoustic phonons at a carrier 

Using the layer thickness, we get a bulk conductivity of 0.96 x 10 cm for graphene. This is somewhat higher than the conductivity of copper which is 0.60 x 10 cm.  

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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]). 

Two-dimensional nanostructures have two dimensions outside of the nanometric size range, such as nanoplates, nanosheets, and nanodisks. Graphene is a typical two-dimensional film, which is composed of a one-atom-thick planar sheet of sp -bonded carbon atoms that are densely packed into a honeycomb crystal lattice. This material exhibits a high electrical conductivity, a high surface area of over 2600 m g , an elevated chemical tolerance, and a broad electrochemical window. Therefore, they were used to form two-dimensional nanocomposites with polymers. The graphene not only increases the electrical conductivity of the polymer, but also enhance its mechanical stability. Conducting polymers with various hierarchical structures have been deposited on... 

The three-dimensional continuous nanostructured framework has a large specific surface area and favors rapid electron and ion transport in polymer-based electronics. The previously mentioned polymer composites with three kinds of structures can form three-dimensional porous structures when they were stacked. Besides, polymers can be incorporated into porous silica, carbon, and graphene as the retaining frameworks to form three-dimensional structured composites. The resultant composite materials exhibit surface properties of the polymers and high mechanical strength and high electric conductivity of the frameworks, which will provide new possibilities for advanced applications. The structures, such as the cormectivity, pore diameters, and shapes, are mainly decided by the frameworks. 

HGURE 4.4 Electrical properties of polymer composites. (A) The electrical conductivity of the PS/graphene composite as a function of graphene volume fraction. (B) The electrical conductivity of directly mixing (DM) CNT/PANI and CNT/ PANI nanofibers with different CNT contents in the directions being parallel and perpendicular to the fiber axis. 

However, the electrical conductivity of the carbon nanomaterials is vulnerable to degradation due to the inefficient dispersion in a large-scale actuator. To this end, some metallic additives have been incorporated into the carbon-based electrode to enhance the electrical conductivity and actuation stability For instance, for the IPMC actuator where the reduced graphene oxide was used as electrode, the electrical conductivity of the electrodes could be efficiently improved after introduction of Ag nanoparticles (Fig. 8.2E) (Lu et al., 2013). As a result, both the actuation frequency and stability could be improved. Upon application of a low voltage of 1V, the actuator could be driven at a wide frequency range (0.01-10 Hz), and no obvious decrease in displacement was observed over 500 cycles of actuation. 

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