Tuesday, October 5, 2010

Graphene: 2D Rock Star

newscientist - New Scientist asked Andre Geim, co-winner of the 2010 Nobel prize for physics, to explain the importance of graphene and other 2D materials as part of our forthcoming "50 ideas to change science forever" special. Here's what he wrote:

Everything in our three-dimensional world has a width, length and height. That was what we thought, at least. But this picture overlooks a whole class of materials: crystals one atom or molecule thick, essentially two-dimensional planes of atoms shaved from conventional crystals.

These are turning out to be wonder materials. Take graphene, the single layers of carbon atoms arranged in a honeycomb lattice that my colleagues and I first isolated in 2004. Graphene is stronger and stiffer than diamond, yet can be stretched by a quarter of its length, like rubber. Its surface area is the largest known for its weight.

Despite graphene's thinness it is impermeable to gases or liquids. It conducts heat and electricity better than copper, and can be made into transistors which are faster than those made from silicon.

It makes possible experiments with high-speed quantum particles that researchers at CERN near Geneva, Switzerland, can only dream of.

With such an array of properties, there are high hopes for what we might accomplish with graphene. Optimists say we are entering a carbon age. Even pessimists argue only that the impact will be somewhat less.

**********

Graphene Finally Goes Big

sciencemag - Graphene: single-atom–thick sheets of carbon prized for its off-the-charts ability to conduct electrons and for being all but transparent. Those qualities make graphene a tantalizing alternative for use as a transparent conductor, the sort now found in everything from computer displays and flat panel TVs to ATM touch screens and solar cells. But the material has been tough to manufacture in anything larger than flakes a few centimeters across. Now researchers have managed to create rectangular sheets of graphene 76 centimeters in the diagonal direction and even use them to create a working touch-screen display.

That scientists can make any devices at all from graphene is impressive. The carbon sheets were isolated only in 2004. Since then, researchers have struggled to produce large swaths of the ultrathin membrane. Last year, a group led by University of Texas, Austin, chemist Rodney Ruoff took a key step, growing graphene squares one centimeter on a side atop flexible copper foils.

Now researchers led by Jong-Hyun Ahn and Byung Hee Hong of Sungkyunkwan University in South Korea report online today in Nature Nanotechnology that they have essentially scaled up the approach taken by the Texas team to make graphene sheets large enough for full-screen displays.

The Korean-led researchers first used a technique called chemical vapor deposition to grow graphene atop large sheets of copper foil. They then added a thin adhesive polymer layer atop the graphene and dissolved away the copper backing. Peeling off the adhesive polymer gave them a single graphene sheet. To make their film stronger, they repeated the initial steps, layering four sheets of graphene atop one another. The researchers then chemically treated their graphene sandwich with nitric acid to improve its electrical conductivity.

The film allowed 90% of light to pass through and had an electrical resistance lower than that of the standard transparent conductor made from indium tin oxide (ITO). The team members also revealed that graphene outperformed ITO when they incorporated it into a real touch-screen display. ITO is used in touch screens, such as those used to record signatures when customers make a credit-card purchase. But it's brittle. Ahn and colleagues showed that their graphene-based touch screen could handle twice as much strain as conventional ITO-based devices.

"It's potentially a really important step along the way for massive scale up" of graphene technology, Ruoff says of the new work. But he cautions that beating out ITO won't be easy. Electronics companies have been working for years to replace ITO with transparent conductors made from films of carbon nanotubes. But they've been undone by small defects in the films that create dead pixels in displays, something the eye can readily see. Still, the indium in ITO is extremely expensive, which ought to give companies every incentive to give graphene a shot at replacing it, says Ruoff.


Have you had a close encounter or witnessed something unusual?
Send us an email


'Phantoms and Monsters' - Now Available on Kindle



New Items - Strickler's Celebrity Autographs


Photobucket
ANOMALIST BOOKS
Works on maverick science, unexplained mysteries, unorthodox theories, strange talents, and unexpected discoveries. Please check out their excellent and diverse catalog



The 'C' Influence
Actualizing Esoteric Discussion


Become a fan of 'Phantoms and Monsters' at Facebook
Photobucket



"The latest news from beyond the mainstream"
Join Ben & Aaron for their weekly podcast!
Check out Mysterious Universe Plus+ all access format!



Spirit Rescue International
Providing no cost professional spiritual help, personal support and guidance
Take the first step towards genuine peace of mind

SPIRIT RESCUE INTERNATIONAL - HAUNTED HELP
Spiritual, paranormal and supernatural guidance and support using remote viewing and other complementary therapies - all are welcome


Join the
Phantoms & Monsters Wiki
A NETWORK OF INVESTIGATORS, ENTHUSIASTS AND THOSE SEEKING THE TRUTH
THROUGH PARANORMAL EDUCATION AND DISCUSSION