Graphene transistors visible on a piece of flexible plastic. Graphene is not only the hardest material in the world, but also one of the most pliable. (Click Image To Enlarge)
I just want to say one word to you. Just one word.
No, fans of “The Graduate,” the word isn’t “plastics.”
Graphene is the strongest, thinnest material known to exist. A form of carbon, it can conduct electricity and heat better than anything else. And get ready for this: It is not only the hardest material in the world, but also one of the most pliable.
Only a single atom thick, it has been called the wonder material.
Graphene could change the electronics industry, ushering in flexible devices, supercharged quantum computers, electronic clothing and computers that can interface with the cells in your body.
While the material was discovered a decade ago, it started to gain attention in 2010 when two physicists at the University of Manchester were awarded the Nobel Prize for their experiments with it. More recently, researchers have zeroed in on how to commercially produce graphene.
The American Chemical Society said in 2012 that graphene was discovered to be 200 times stronger than steel and so thin that a single ounce of it could cover 28 football fields. Chinese scientists have created a graphene aerogel, an ultralight material derived from a gel, that is one-seventh the weight of air. A cubic inch of the material could balance on one blade of grass.
Dr. Aravind Vijayaraghavan, a lecturer at the University of Manchester, said.
“Graphene is one of the few materials in the world that is transparent, conductive and flexible — all at the same time. All of these properties together are extremely rare to find in one material.”
So what do you do with graphene? Physicists and researchers say that we will soon be able to make electronics that are thinner, faster and cheaper than anything based on silicon, with the option of making them clear and flexible. Long-lasting batteries that can be submerged in water are another possibility.
In 2011, researchers at Northwestern University built a battery that incorporated graphene and silicon, which the university said could lead to a cellphone that “stayed charged for more than a week and recharged in just 15 minutes.” In 2012, the American Chemical Society said that advancements in graphene were leading to touch-screen electronics that “could make cellphones as thin as a piece of paper and foldable enough to slip into a pocket.”
Dr. Vijayaraghavan is building an array of sensors out of graphene — including gas sensors, biosensors and light sensors — that are far smaller than what has come before.
Scientists at Samsung's Advanced Institute of Technology (SAIT) and Sungkyunkwan University in South Korea discovery a new method for growing large area, single crystal wafer scale graphene. (Click Image To Enlarge)
And in April 2014, researchers at the Samsung Advanced Institute of Technology, working with Sungkyunkwan University in South Korea, said that Samsung had figured out how to create high-quality graphene on silicon wafers, which could be used for the production of graphene transistors. Samsung said in a statement that these advancements meant it could start making “flexible displays, wearables and other next-generation electronic devices.”
Sebastian Anthony, a reporter at Extreme Tech, said that Samsung’s breakthrough could end up being the “holy grail of commercial graphene production.”
Samsung is not the only company working to develop graphene. Researchers at IBM, Nokia and SanDisk have been experimenting with the material to create sensors, transistors and memory storage.
When these electronics finally hit store shelves, they could look and feel like nothing we’ve ever seen.
James Hone, a professor of mechanical engineering at Columbia University, said research in his lab led to the discovery that graphene could stretch by 20 percent while still remaining able to conduct electricity. He said.
“You know what else you can stretch by 20 percent? Rubber. In comparison, silicon, which is in today’s electronics, can only stretch by 1 percent before it cracks.”
“That’s just one of the crazy things about this material — there’s really nothing else quite like it.”
The real kicker? Graphene is inexpensive.
If you think of something in today’s electronics industry, it can most likely be made better, smaller and cheaper with graphene.
Berkeley creates the first graphene earphones, and (unsurprisingly) they’re awesome. (Click Image To Enlarge)
Scientists at the University of California, Berkeley made graphene speakers last year that delivered sound at quality equal to or better than a pair of commercial Sennheiser earphones. And they were much smaller.
Another fascinating aspect of graphene is its ability to be submerged in liquids without oxidizing, unlike other conductive materials.
As a result, Dr. Vijayaraghavan said, graphene research is leading to experiments where electronics can integrate with biological systems. In other words, you could have a graphene gadget implanted in you that could read your nervous system or talk to your cells.
But while researchers believe graphene will be used in next-generation gadgets, there are entire industries that build electronics using traditional silicon chips and transistors, and they could be slow to adopt graphene counterparts.
If that is the case, graphene might end up being used in other industries before it becomes part of electronics. Last year, the Bill and Melinda Gates Foundation paid for the development of a graphene-based condom that is thin, light and impenetrable. Carmakers are exploring building electronic cars with bodies made of graphene that are not only protective, but act as solar panels that charge the car’s battery. Airline makers also hope to build planes out of graphene.
If all that isn’t enough, an international team of researchers based at M.I.T. has performed tests that could lead to the creation of quantum computers, which would be a big market of computing in the future.
So forget plastics. There’s a great future in graphene. Think about it.
COMMENTARY: Graphene may be one of the strongest materials on the planet, but a new study raises questions about the limits of using it in the real world.
When material scientists measured the fracture toughness of imperfect graphene for the first time, they found it to be somewhat brittle.
While it’s still very useful, graphene is really only as strong as its weakest link, which they determined to be “substantially lower” than the intrinsic strength of graphene.
An electron microscope image shows a pre-crack in a suspended sheet of graphene used to measure the overall strength of the sheet - The Nanomaterials, Nanomechanics and Nanodevices Lab-Rice University. (Click Image To Enlarge)
A pre-cracked sheet of graphene was suspended and pulled apart - The Nanomaterials, Nanomechanics and Nanodevices Lab-Rice University. (Click Image To Enlarge)
Ting Zhu, an associate professor at the Georgia Institute of Technology, says.
“Graphene has exceptional physical properties, but to use it in real applications, we have to understand the useful strength of large-area graphene, which is controlled by the fracture toughness,”
Zhu and Jun Lou, an associate professor at Rice University, report in the journal Nature Communications the results of tests in which they physically pulled graphene apart to see how much force it would take. Specifically, they wanted to see if graphene follows the century-old Griffith theory that quantifies the useful strength of brittle materials.
It does, Lou says.
“Remarkably, in this case, thermodynamic energy still rules.”
PERFECT VS. IMPERFECT
Imperfections in graphene drastically lessen its strength—with an upper limit of about 100 gigapascals (GPa) for perfect graphene previously measured by nanoindentation—according to physical testing at Rice and molecular dynamics simulations at Georgia Tech.
That’s important for engineers to understand as they think about using graphene for flexible electronics, composite material, and other applications in which stresses on microscopic flaws could lead to failure.
The Griffith criterion developed by a British engineer during World War I describes the relationship between the size of a crack in a material and the force required to make that crack grow. Ultimately, A.A. Griffith hoped to understand why brittle materials fail.
Graphene, it turns out, is no different from the glass fibers Griffith tested.
“Everybody thinks the carbon-carbon bond is the strongest bond in nature, so the material must be very good, but that’s not true anymore, once you have those defects. The larger the sheet, the higher the probability of defects. That’s well known in the ceramic community.”
A defect can be as small as an atom missing from the hexagonal lattice of graphene. But for a real-world test, the researchers had to make a defect of their own—a pre-crack—they could actually see.
“We know there will be pinholes and other defects in graphene. The pre-crack overshadows those defects to become the weakest spot, so I know exactly where the fracture will happen when we pull it."
“The material resistance to the crack growth—the fracture toughness—is what we’re measuring here, and that’s a very important engineering property.”
Additional researchers from Rice, Georgia Tech, Nanyang Technological University in Singapore, and at Tianjin Polytechnic University in China collaborated on the project, which received support from Welch Foundation, the National Science Foundation, the US Office of Naval Research, and the Korean Institute of Machinery and Materials.