Graphene: Physics, Breakthroughs, Impact on the World

[okarin314]

What is graphene from a physics standpoint? Why do I keep hearing that graphene is considered to be such a major breakthrough? How is graphene going to transform the world?

 

[jedishrfu]

Wikipedia describes it pretty well:

http://en.wikipedia.org/wiki/Graphene

Basically its very strong, lightweight and novel with many unique properties. Engineers love this stuff and try design devices that use it.Here are some uses:

http://en.wikipedia.org/wiki/Potential_applications_of_graphene

 

[UltrafastPED]

What is graphene from a physics standpoint? Why do I keep hearing that graphene is considered to be such a major breakthrough? How is graphene going to transform the world?

It is essentially a new state of matter - a solid that is only one atom thick. This means that it has quantum mechanical properties which cannot be ignored ... and they can be taken advantage of.

It will not change the world overnight, but you will see new applications appearing on a regular basis, every year, until it will be as commonplace as silicon is today, though they will often be used together: the old and the new.

One novel application: a layer of graphene can be used to trap helium gas - the gas atoms are too small to fit through the "holes" in graphene, so the leakage rate is very low (but not zero). This means that a device can be made with a graphene window, but be filled with helium. This is the solution to some engineer's problem - and it wasn't previously available!

 

[Lok]

Graphene is not novel. Yet our interest in it is.

Beside the more useful uses stated above. It is worth mentioning that it behaves mechanically a lot like Carbon Fiber yet it has it's properties in 2 dimensions. So you could use it to coat/reinforce structural beams and surfaces just as Carbon fiber is used today, without the weave weakness of CF. It's Young's Modulus is slightly higher than Carbon nano-tubes and slightly lower than Diamond, and around 4 times higher than CF. Mechanically if it can be made into large enough sheets it will enable a huge weight reduction in structural applications .

 

[UltrafastPED]

Graphene is not novel.

Sure it is ... it was thought to be impossible prior to the demonstration of its existence in 2004! So all of the practical research has been in the last few years!

Graphene (and other 2D materials) are just getting started. Novel = New.

 

[Lok]

Sure it is ... it was thought to be impossible prior to the demonstration of its existence in 2004! So all of the practical research has been in the last few years!

Graphene (and other 2D materials) are just getting started. Novel = New.

I meant that it was in nature all along in graphite. Let's not forget the details of it's "discovery".
http://en.wikipedia.org/wiki/Graphene#mediaviewer/File:Nobelpriset_i_fysik_2010.tif

I did not know it was thought of as impossible though.

 

[UltrafastPED]

I meant that it was in nature all along in graphite. Let's not forget the details of it's "discovery".
http://en.wikipedia.org/wiki/Graphene#mediaviewer/File:Nobelpriset_i_fysik_2010.tif

Yes ... I've spent many hours with this technique, and even managed to isolate a bunch of graphene flakes, ~ 30 um in diameter. From the color you can estimate the number of layers, from about 1 to 10. But these were too small for what I wanted to do.

I did not know it was thought of as impossible though.

An analysis of the potential energy shows that it will "roll up" - this analysis was done in the 1920s, and I think Landau repeats the calculation; the calculation is convincing, as it minimizes the surface energy.

However, nature is tricky: rolling up is a nice smooth process; in reality it buckles. The calculation to show that buckling results in less energy cannot be done analytically; you have to run a finite element type analysis on it. This was not done until after it was discovered, AFAIK.

This is a good introductory paper: "THE RISE OF GRAPHENE", by A.K. Geim and K.S. Novoselov
http://arxiv.org/ftp/cond-mat/papers/0702/0702595.pdf