Honeycomb carbon: A review of graphene

Graphene is the name given to a two-dimensional sheet of sp ²-hybridized carbon. Its extended honeycomb network is the basic building block of other important allotropes; it can be stacked to form 3D graphite, rolled to form 1D nanotubes, and wrapped to form 0D fullerenes. Substrate-based growth of single layers by chemical vapor deposition (CVD) or the reduction of silicon carbide relies on the ability to walk a narrow thermodynamic tightrope. Graphite has a rich chemistry in which it can participate in reactions as either a reducing agent (electron donor) or an oxidizer (electron acceptor). Solution processing of chemically derived graphene and the depositions achieved soon led researchers to consider using the material in transparent conductors. The graphite oxide has produced the first chemically derived micrometer-scale graphene, synthetic techniques for smaller planar, benzene-based macromolecules.