Sunday, 30 September 2012

Graphene


Carbon is the stuff of life, the foundation of every living thing. We go to war over it as oil and diamond, and we take it for granted whenever we need a pencil.
But for all of its pervasive familiarity, it is also capable of some seriously strange behaviour.
Take carbon nanotubes, for instance: sheaths of carbon atoms rolled into cylinders with diameters roughly 10,000 times smaller than a human hair, they are tinier than can be easily imagined. But they are also incredibly strong, and wonderfully conductive. They've made their way into science fiction, and increasingly into real-world applications.
For example, research back in 2008 showed that adding carbon nanotubes to normal carbon fibre at just a one-percent concentration increases the material's strength by 64 percent. Other research institutions are working on ways of spinning the nanotubes into cloth to make lightweight and flexible body armour.
And what about buckyballs — another member of the fullerene family? These football-shaped arrangements of 60 carbon atoms have even been found out in space, and some suggest they might even be responsible for seeding Earth with the ingredients of life. Their discovery won the 1996 Nobel Prize for Chemistry for Harold W Kroto, Robert F Curl and Richard E Smalley.
But we don't need to consider the alien. Even the most familiar forms of carbon hold a few surprises.

Let's revisit the graphite pencil lead. Zoom in and you'll see layer upon layer of carbon atoms arranged in a hexagonal honeycomb structure, each two-dimensional plane loosely bonded to its neighbours.

Pencil lead

It works so nicely as a writing material and industrial lubricant because although the carbon atoms in each layer are strongly bonded in connecting hexagons, the layers slip easily over one another, leaving a silvery trail behind.
Each of those layers, though, could revolutionise electronics and engineering. Each of those layers is a material that — unless you have been living under a large lump of coal — you might have heard of: graphene.

Enter graphene

Discovered by Professor Andre Geim and Dr Kostya Novoselov, graphene is a single layer of graphite. It is a lattice of hexagons, each vertex tipped with a carbon atom. At the molecular level, it looks like chickenwire.
It has written its own book of superlatives. It is the thinnest possible material you can imagine, one of the most transparent, the most conductive, the most mechanically strong, the most elastic and so on.
Six years ago, it didn't exist at all, and next year we know that Samsung is planning to release their first mobile-phone screens made of graphene.
– Dr Kostya Novoselov
It is also the material that has moved most quickly from discovery to application in modern times. "Six years ago, it didn't exist at all, and next year we know that Samsung is planning to release their first mobile-phone screens made of graphene," Dr Novoselov said in an interview.
While investigating graphite's potential as a transistor ("It did work, up to some extent," Novoselov said), the pair became interested in making the thinnest possible slices of the material. Eventually, using sticky tape, they pulled a single layer free and found that isolated from the rest of the graphite stack, its properties were mind blowing.
The rest is history and the future of technology.

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