Graphene

Graphene

About Graphene:

  • Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a Hexagonal lattice nanostructure.
  • The name is derived from “graphite” and the suffix  ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds.
  • Graphene is a single layer (monolayer) of carbon atoms, tightly bound in a hexagonal honeycomb lattice.
  • It is an allotrope of carbon in the form of a plane of sp2-bonded atoms with a molecular bond length of 0.142 nanometres.
  • Each atom in a graphene sheet is connected to its three nearest neighbors by σ-bonds and a delocalised π-bond, which contributes to a valence band that extends over the whole sheet.
  • This is the same type of bonding seen in carbon nanotubes and polycyclic aromatic hydrocarbons, and (partially) in fullerenes and glassy carbon.

Properties:

  • Graphene sheet is thermodynamically unstable if its size is less than about 20 nm and becomes the most stable fullerene (as within graphite) only for molecules larger than 24,000 atoms.
  • Graphene is a zero-gap semiconductor, because its conduction and valence bands meet at the Dirac points.
  • Graphene’s permittivity varies with frequency. Over a range from microwave to millimeter wave frequencies it is roughly 3.3.
  • This permittivity, combined with the ability to form both conductors and insulators, means that theoretically, compact capacitors made of graphene could store large amounts of electrical energy.

Potential applications:

Graphene is an extremely diverse material, and can be combined with other elements (including gases and metals) to produce different materials with various superior properties. Researchers all over the world continue to constantly investigate and patent graphene to learn its various properties and possible applications, which include:

Syllabus: Prelims

CIVIL SERVICES EXAM