What is Graphene?

Graphene has been talked about in glowing terms with scientists suggesting confidently it is the key to the future of almost all materials. So revolutionary are its qualities they even talk of the “graphene age”.

Graphene is a natural material which is the basic building block of graphite, achieved when the thickness is reduced to less than 10 atoms. Though it was “discovered” in the 1940s, it took until 2004, before scientists figured out how to isolate it from graphite particles, using the simple “scotch tape” exfoliation method. Since then there has been tremendous interest in graphene with research scientists demonstrating its suitability for combination with a vast range of materials, to greatly enhance the performance of those materials. There has also been an explosion in the number of patents being taken out as industry has been preparing for the start of the new and deeply disruptive “graphene age”. The key properties of graphene that industry is seeking to employ are as follows:.

Thinnest material
It is only one carbon atom in thickness i.e. only ~0.345 nm thick.

Stronger than steel
It is one of the hardest materials in the world, being harder than diamonds and 200x stronger than steel (1,100TPa/125 GPa) of the same thickness but it is very flexible and will not break. As an example, a graphene sheet 1 m2 in size could support a 4 kg cat, but that sheet would weigh only as much as the cat’s whiskers (1).

Optical properties
One atom thick layer sheets absorb ~2.3% visible light, making it transparent.

Light and stretchable
It weighs only 0.77 milligrams per square meter and is stretchable up to 20% of its initial length. It has the largest volume to surface area ratio of any material.

It is completely impermeable. Even helium atoms cannot pass through it.

Thermal conductivity
It is a perfect thermal conductor (over 5,000 W/mK), being 5x the conductivity of graphite. It conducts heat in all directions i.e. it is an isotropic conductor.

Electronic properties
It has the highest electrical current density (one million times that of copper) and the highest intrinsic mobility (100x that of silicon). It has a lower resistivity than any other know material, at room temperature.

Chemical properties
It is an inert material and does not readily react with other atoms. However, it can “absorb” different atoms and molecules, leading to changes in its properties. It can be functionalised by several different chemical groups, resulting in different materials such as graphene oxide and fluorinated graphene.

Other qualities
Self-repairing - graphene can self-repair holes in its sheets when exposed to molecules containing carbon. Reactive - it is the most reactive form of carbon.

Useful Links Describing Graphene and its Potential

Graphene on the One Show

Graphene Science - Mikael Fogelstrom - TEDx

Graphene Supercapacitor

Graphene: The Material of Tomorrow

Graphene Synthesis & Applications