FYI...
Graphene
So,
graphene is fundamentally one single layer of graphite; a layer of sp2 bonded carbon atoms arranged in a honeycomb (hexagonal) lattice. However,
graphene offers some impressive properties that exceed those of graphite as it is isolated from its ‘mother material’. Graphite is naturally a very brittle compound and cannot be used as a structural material on its own due to its sheer planes (although it is often used to reinforce steel). Graphene, on the other hand, is the strongest material ever recorded, more than three hundred times stronger than A36 structural steel, at 130 gigapascals, and more than forty times stronger than diamond.
Due to graphite’s planar structure, its thermal, acoustic and electronic properties are highly anisotropic, meaning that phonons travel much more easily along the planes than they do when attempting to travel through the planes. Graphene, on the other hand, being a single layer of atoms and having very high electron mobility, offers fantastic levels of electronic conduction due to the occurrence of a free pi (π) electron for each carbon atom.
However, for this high level of electronic conductivity to be realised, doping (with electrons or holes) must occur to overcome the zero density of states which can be observed at the Dirac points of graphene. The high level of electronic conductivity has been explained to be due to the occurrence of quasiparticles; electrons that act as if they have no mass, much like photons, and can travel relatively long distances without scattering (these electrons are hence known as massless Dirac fermions).
Creating Or Isolating Graphene
There are a number of ways in which scientists are able to produce graphene. The first successful way of producing monolayer and few layer graphene was by mechanical exfoliation (the adhesive tape technique). However, many research institutions around the world are currently racing to find the best, most efficient and effective way of
producing high quality graphene on a large scale, which is also cost efficient and scalable.
The most common way for scientists to create monolayer or few layer graphene is by a method known as chemical vapour deposition (CVD). This is a method that extracts carbon atoms from a carbon rich source by reduction. The main problem with this method is finding the most suitable substrate to grow graphene layers on, and also developing an effective way of removing the graphene layers from the substrate without damaging or modifying the atomic structure of the graphene.
Other methods for creating graphene are: growth from a solid carbon source (using thermo-engineering), sonication, cutting open carbon nanotubes, carbon dioxide reduction, and also graphite oxide reduction. This latter method of using heat (either by atomic force microscope or laser) to
reduce graphite oxide to graphene has received a lot of publicity of late due to the minimal cost of production. However, the quality of graphene produced currently falls short of theoretical potential and will inevitably take some time to perfect.
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