What is graphene?

Want to win a Nobel prize while discovering a material that’s cheap, transparent, flexible but resistent, and an astonishing electric conductor? Grab a pencil and a roll of adhesive tape. I’m serious.

Pencil leads are made of graphite, a form of carbon made of layers of atoms organized in hexagonal cells, like a bee hive. Atoms on the same layer stick together tightly, but are much more loosely attached to the next layer. So, when we write, a few layers peel off the tip and go to the paper.

CC-BY-SA AlexanderAlUS via commons

The sci-fi tech that lead to the discovery of graphene
credit: WikimediaImages/pixabay

If graphite sounds like graphene, it’s because they’re pretty much the same thing. Andre Geim and Konstan Novoselov (who won the Nobel prize for their discovery) created graphene for the first time by repeatedly sticking tape to graphite and ripping it off. Every time a few layers would stick to the tape, until what was left was a single atom thick.

Because it’s so thin, graphene has only the properties of the carbon layer. Without interference from the other layers, it doesn’t behave like a pencil’s graphite anymore. Instead, it supercharges its properties.

For example, each atom is somewhat willing to part with four of its electrons. In a graphene sheet, the atom only has three neighbors to share electrons with, so one is pretty much free to leave and roam around. This makes graphene extremely conductive. If the electrons were busy sticking to other layers (as in graphite) the material would conduct less.

Being so thin, graphene is rather transparent, and very light. But it’s also spectacularly strong (more than steel), thanks to the strong bonds between its atoms.

Thanks to its fantastic properties, graphene is the protagonist of countless works in material science. Electronic devices cannot ask for better than a very conductive material, that doesn’t break and can be used for touch screens.

Making big enough sheets isn’t easy, though, so it still takes a while to have industrial-scale use of graphene.

And if you still want that Nobel prize, I’m afraid the sticky tape and pencil way is taken.

If you want more

Cover photo: Graphene, CC-BY-NC-SA Martin Griffiths/flickr

Phenomenal cosmic power, itty bitty living space

Wouldn’t it be great to take the universe in the lab? Astronomy is one of the most captivating parts of physics. I mean, one can’t scoff at the idea of unveiling the mysteries of the cosmos. Unfortuntely, galaxies and black holes don’t exactly cooperate as far as experimenting goes.

A group of physicists is working on a solution.

As it turns out, bottling the immense cosmos in a handful of atoms is but one of the amazing properties of graphene. Graphene is a very thin sheet of carbon, just a single atom thick, all arranged in hexagons like cells in a beehive. Normally, then, each cell has six atoms, but scientists can add or remove one here and there, making some cells with five or seven.

CC-BY-SA AlexanderAlUS via commons

The normal structure of graphene lets a few electrons (one per atom, precisely) rather free to roam around. Cells with one atom more or less mess up this nice order. Electrons can’t just skip around carefree, instead they are attracted to five-atom cells and repelled by seven-atom ones. This creates a little bit of electric current in the material.

Big whoop.

Here comes the cool part, though: this current seems to bend exactly as how spacetime does according to General Relativity. So, appropriately placing atoms, you could simulate fantastically large cosmic phenomena in teeny tiny devices.

An example of wormhole in two-dimensional space-time. credit: telegraph.co.uk

For example, the researchers connected two sheets of graphene to simulate a wormhole—the hypothetical tunnel connecting two far-apart regions of spacetime, like in Interstellar.

The research is still just theoretical, but a tangible prototype should be just around the corner. The researchers say that it should have plenty of applications for electronic devices.

Personally, I’m also interested in holding the (ok, simulated) forces of gravity in the palm of my hand.

If you want more
  • The study isn’t published on journals yet. As far as I understand it’s about to be, in the meantime you can find the manuscript here

Cover photo: CC-BY-SA Karl Wienand, (using felixioncool, WikiImages, skeeze)