Graphene in Space

Honeycomb Carbon Crystals Possibly Detected in Space

Graphene in Space: An artist's concept of graphene, buckyballs and C70 superimposed on an image of the Helix planetary nebula, a puffed-out cloud of material expelled by a dying star.

NASA’s Spitzer Space Telescope has spotted the signature of flat carbon flakes, called graphene, in space. If confirmed, this would be the first-ever cosmic detection of the material — which is arranged like chicken wire in flat sheets that are one atom thick.

Graphene was first synthesized in a lab in 2004, and subsequent research on its unique properties garnered the Nobel Prize in 2010. It’s as strong as it is thin, and conducts electricity as well as copper. Some think it’s the “material of the future,” with applications in computers, screens on electrical devices, solar panels and more.

Graphene in space isn’t going to result in any super-fast computers, but researchers are interested in learning more about how it is created. Understanding chemical reactions involving carbon in space may hold clues to how our own carbon-based selves and other life on Earth developed….. Continue reading Graphene in Space

Graphene gives up more of its secrets

Undoped graphene isn't a metal, semiconductor, or insulator but a semimetal, whose unusual properties include electron-electron interactions between particles widely separated on graphene's honeycomb lattice -- here suggested by an artist's impression of the Feynman diagrams often used to keep track of such interactions. Interactions occur over only very short distances in ordinary metals. Long-range interaction alter the fundamental character of charge carriers in graphene

Graphene, a sheet of carbon only a single atom thick, was an object of theoretical speculation long before it was actually made. Theory predicts extraordinary properties for graphene, but testing the predictions against experimental results is often challenging.

Now researchers using the Advanced  (ALS) at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have taken an important step toward confirming that graphene is every bit as unusual as expected – perhaps even more so.

“Graphene is not a semiconductor, not an insulator, and not a metal,” says David Siegel, the lead author of a paper in the Proceedings of the National Academy of Sciences (PNAS) reporting the research team’s results. “It’s a special kind of semimetal, with electronic properties that are even more interesting than one might suspect at first glance.”…. Continue reading Graphene gives up more of its secrets

Graphene integrated circuit is a first

Two inductors and a transistor: Photograph of the graphene integrated circuit showing the inductors, which are the two large square structures at the top left and right. The field effect transistor is the tiny structure at the cross in the centre of the photograph.

IBM researchers have made the first graphene circuit in which all of the circuit elements are integrated on a compact single chip. The new circuit is another important step forward for graphene-based electronics and potential applications include wireless communications and amplifiers…..
Read more: http://physicsworld.com/cws/article/news/46237

Graphene may reveal the grain of space-time

Call that a spin?

COULD the structure of space and time be sketched out inside a cousin of plain old pencil lead? The atomic grid of graphene may mimic a lattice underlying reality, two physicists have claimed, an idea that could explain the curious spin of the electron.
Graphene is an atom-thick layer of carbon in a hexagonal formation. Depending on its position in this grid, an electron can adopt either of two quantum states – a property called pseudospin which is mathematically akin to the intrinsic spin of an electron…. Continue reading Graphene may reveal the grain of space-time

How To Make Graphene Paper

A new model predicts the properties of paper made from graphene sheets

(a) The distribution of intralayer tensile forces F(x) along the profile of the graphene sheets, showing linear behavior for small graphene sheets, and a flat region when the graphene sheet size increases. Correspondingly (b) gives similar plots for shear strain γ(x) between adjacent graphene sheets. No intralayer crosslink is taken into account here. The inset shows the ratio between the maximum shear strain γmax in the DTS model and γrigid in the rigid approximation for graphene sheets with different lengths.

Carbon fibres were developed in the 1950s and have since helped to revolutionise the design, manufacture and performance of everything from yachts and planes to cars and bicycles.
Now, 60 years later, a new material looks set to have a similar impact: graphene paper.
For the moment, it’s only possible to make graphene in tiny scraps. So the trick in scaling it up is to find ways to stack these sheets and bond them together to make something larger. Trouble is nobody has yet managed this feat.
Today, Yilun Liu and pals at Tsinghua University in Beijing, calculate from first principles what such a material might be like.
The trick in making graphene paper strong is to find ways to bind small sheets of graphene together end-to-end to make a larger sheet but also to bind layers together using bonds between them. Many biological materials use the same trick to increase their strength, materials such as bone, teeth and nacre.
Of course, these materials are only as strong as their weakest link. So Yilun and co have calculated what sort of strength we can expect from graphene paper.
Their answer is that it depends on the types of cross-links, their strength, number and whether they reform quickly after they are broken as epoxy and hydroxyl groups do.
This approach allows engineers to design the material accordingly. In fact, the new model can be used to design other papers too so it may be possible to improve the properties of all kinds of thin, layered sheets.
Yilun and co’s model makes a number of interesting predictions. For example, it says the links between graphene layers will increase the distance between them, thereby reducing the density to about half that of graphite. So graphene paper is not only going to be strong but also very light.
All it needs now is somebody to go ahead and create a sheet of this stuff. And if it can one day be made cheaply and easily enough we’ll see it everywhere–both inside and outside our bodies.
http://www.technologyreview.com/blog/arxiv/26729/
http://arxiv.org/ftp/arxiv/papers/1105/1105.0138.pdf