#7: The Graphene Revolution

Flexible, see-through, one-atom-thick sheets of carbon could be a key component for futuristic solar cells, batteries, and roll-up LCD screens—and perhaps even microchips.

By Elizabeth Svoboda|Monday, January 25, 2010

Graphene's atom-thin sheets shown here in an artist's rendering, let electrons pass through rapidly.

Jannik Meyer

Under a transmission electron microscope it looks deceptively simple: a grid of hexa­gons resembling a volleyball net or a section of chicken wire. But graphene, a form of carbon that can be produced in sheets only one atom thick, seems poised to shake up the world of electronics. Within five years, it could begin powering faster and better transistors, computer chips, and LCD screens, according to researchers who are smitten with this new supermaterial.

Graphene’s standout trait is its uncanny facility with electrons, which can travel much more quickly through it than they can through silicon. As a result, graphene-based computer chips could be thousands of times as efficient as existing ones. “What limits conductivity in a normal material is that electrons will scatter,” says Michael Strano, a chemical engineer at MIT. “But with graphene the electrons can travel very long distances without scattering. It’s like the thinnest, most stable electrical conducting framework you can think of.”

In 2009 another MIT researcher, Tomas Palacios, devised a graphene chip that doubles the frequency of an electromagnetic signal. Using multiple chips could make the outgoing signal many times higher in frequency than the original. Because frequency determines the clock speed of the chip, boosting it enables faster transfer of data through the chip. Graphene’s extreme thinness means that it is also practically transparent, making it ideal for transmitting signals in devices containing solar cells or LEDs.

The big limitation of graphene is that it is not a true semiconductor. Unlike silicon, it cannot be switched on and off to create circuits, which will limit its use in electronics. “In mainstream digital applications, you will not see graphene displace silicon,” Columbia University electrical engineer Ken Shepard insists. But other researchers are already expanding graphene’s capabilities. In June materials scientist Feng Wang of the University of California at Berkeley announced a method to tune the material electrically to give it switching properties. That would enable graphene to form extremely small, fast transistors.

Even without switching, Strano thinks graphene will find many uses—as a flexible conductor in thin-film batteries or roll-up LCD screens, for instance. “I’m most excited about the applications we have yet to discover,” he says. “Graphene is an out-of-the-box material, so we shouldn’t try to hammer it into existing boxes.”

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