Graphos

What is graphene

GRAPHENE

Graphene is a single layer of carbon atoms, arranged in honeycomb lattice to form a bidimensional monocrystal. Each graphene sheet has a thickness of one atom, and can extend laterally for hundreths of microns.   Graphene is therefore the thinnest material existing in nature; even if one atom thick, the sheets are robust and stable in air; they can be processed mechanically, dissolved in solvents and deposited on different substrates.

Andre Geim and Konstantin Novoselov, which firstly discovered graphene in 2004, recently received the Nobel Prize in Physics for 2010.

Since its discovery, graphene has attracted interest of both physicists and chemists due to its excellent materials properties. A single sheet of graphene has a typical charge mobility of 15000 cm2V-1s-1 (10 times better than silicon), a Young modulus of 1000 GPa (5 times better than steel), a thermal conductivity of 5000 WmK-1 (10 times better than copper). It shows ballistic transport of electrons at room temperature, tunable hole or electron transport, quantum Hall effect, weak dependence of mobility on temperature. Furthermore, it can be produced, processed and chemically functionalized in organic or aqueous solvents.

Such peculiarity makes graphene a potential materials for many applications:

  • Field-Effect Transistors
  • Ultracapacitor
  • Transparent Films
  • EMI shielding
  • Organic Light-Emitting Diodes
  • Chemical Sensors,
  • High Frequency Devices
  • Optical Devices
  • Biomedical support
  • Additive for coating
  • Additive to improve electrical, thermal or mechanical proprieties of polymer

GRAPHENE OXIDE

A water-soluble, highly processable version of graphene is graphene oxide (GO), which contain epoxy and hydroxyl group on the plane and carboxyl group at the edge. This material, while retaining the original graphene planar sheet structure, has electrical and chemical properties completely different from the ones of graphene. GO can be dissolved in water at high concentrations; the hydroxyl and carboxyl groups on its surface allow GO  to be efficiently modified by reaction with a wide range of chemicals, using standard procedures of organic chemistry. GO is electrically insulating but can, once processed, be reduced back to graphene.

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