Chance Discoveries: Graphene

Air Date: 10/06/2011
Source:
NBC Learn
Creator:
Ron Allen
Air/Publish Date:
10/06/2011
Event Date:
10/06/2011
Resource Type:
Science Explainer
Copyright:
NBCUniversal Media, LLC.
Copyright Date:
2011
Clip Length:
00:04:35

This NBC Learn video, part of a series on "Chance Discoveries" in chemistry, tells the story of two scientists who used their curiosity -- and Scotch tape -- to isolate single-layer sheets of graphite one atom thick: graphene, one of the thinnest, strongest materials known. The two won the 2010 Nobel Prize in Physics for their discovery.


Chance Discoveries -Graphene

RON ALLEN, reporting
When you think of a strong material, steel, metal and wood typically come to mind. But believe it or not, graphene, a single layer of graphite only one atom thick, is stronger than all of them.

ILLONA KRETZCHMAR: Graphene is a one-atom thick layer of carbon, and the carbon is in a hexagonal pattern, and it's one of the thinnest and strongest materials that currently exists in the world.

ALLEN: Graphene was first synthesized in the 1980s, but isolating a single sheet of it was deemed impossible. Scientists thought that graphene’s unique hexagonal structure - sort of like a two-dimensional piece of chicken wire – would cause the material to roll up into a cylinder, much like real chicken wire! How graphene finally came to be isolated into a single flat layer is a tribute to human curiosity, coincidence, and good old luck. It happened in 2004, when Russian physicists Andre Geim and Konstantin Novoselov at the University of Manchester decided to tackle the impossible, and finally isolated this miracle material. To start, they assigned one of their post-doc students to file down a piece of graphite as thin as possible. A few days later, the student returned with his results….

KRETZCHMAR: Geim looked at it and found that it was 10 microns thick, which means that it had 1,000 layers of graphene, and they wanted to get to a single layer.

ALLEN: Next, they turned to a colleague at the university who regularly examined graphite with a scanning tunneling microscope - an extremely sensitive instrument that can take images of material at the atomic level. Geim and Novoselov noticed how the colleague cleaned and prepared the surface of graphite samples with Scotch tape to get rid of any impurities, and that's when the light bulb went off.

KRETZSCHMAR: When Novoselov and Geim saw this technique they were like, 'Oh that's it! This is what we have to do. We have to take a piece of graphite and put it between two pieces of scotch tape and start peeling it off.'

ALLEN: This method, officially known as the "Scotch Tape Technique," worked. Each time they pulled the tape apart, it split the graphite into flakes. Eventually some of those flakes were only one layer thick. Their next challenge was to dissolve the tape in a solvent and deposit the graphene on a silicon dioxide surface. By pure luck, it worked on their first try.

KRETZSCHMAR: The oxide had just the right thickness to then interfere, or cause an interference pattern with the graphene layer which made it visible. The fact that they used the right material and that they had the right method at the right time was a huge coincidence.

ALLEN: The single layer of graphene was also completely stable and, and best of all, it did not roll up into a cylinder.

KRETZSCHMAR: In graphene the electrons are arranged such that they can actully interact with the atoms only within the layer, but don't need the extra atoms on top and on the bottom, and so it's a fascinating stable material because of that.

ALLEN: Geim and Novosolov had discovered a pure material of unprecedented strength with highly conductive properties. It could eventually change the way we use computers and other electronics - making them smaller, faster and stronger.

KRETZSCHMAR: Right now, in computers we use silicon chips, and they are highly brittle. With graphene we can imagine, or scientists are dreaming of having flexible electronics, having a laptop that you can fold together and put in your pocket.

ALLEN: While the material has so far had more promise than application, this new research might change that.

KRETZSCHMAR: They set off a completely new research area by discovering this one atom thick material. They have caused many, many researchers in the world to change their interests to investigate graphene, and I think we will see a lot more in the future.

ALLEN: In 2010, Geim and Novosolov won the Nobel Prize in Physics for their research on graphene, a breakthrough small in size but potentially large in impact.

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