Graphene

Graphene has emerged as one of the most promising nanomaterials because of its unique combination of exceptional properties: it is not only the thinnest but also one of the strongest materials; it conducts heat better than all other materials; it is an excellent conductor of electricity; it is optically transparent, yet so dense that it is impermeable to gases ¿ not even helium, the smallest gas atom, can pass through it.Graphene is the name for a single layer (monolayer) sheet of carbon atoms that are bonded together in a repeating pattern of hexagons. This sheet is only one atom thick. Monolayers of graphene stacked on top of each other form graphite. Since a typical carbon atom has a diameter of about 0.33 nanometers, there are about 3 million layers of graphene in a 1 mm thick sheet of graphite. In scientific terms: The extraordinary characteristics of graphene originate from the 2p orbitals, which form the ¿ state bands that delocalize over the sheet of carbons that constitute graphene. Harder than diamond yet more elastic than rubber; tougher than steel yet lighter than aluminum.