Is Graphene Elvis or the Russell Brand of Materials?
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If there were a Rolling Stone magazine equivalent for the materials science set, graphene would be on the cover. Graphene consists of “single-atom–thick sheets of carbon prized for its off-the-charts ability to conduct electrons and for being all but transparent” (Service). Graphene, like Russell Brand, has some intriguing qualities: it’s extremely strong and highly conductive, which along with its transparency, make it an attractive alternative for use as a transparent conductor. Everything from computer displays and flat panel TVs to ATM touch screens and solar cells use transparent conductors these days, and finding a material that is strong, thin, and flaw-free has been a challenge.
Image credit http://www.lbl.gov
According to Moore’s Law, the density of transistors on an integrated circuit doubles every two years. Silicon and “other existing transistor materials are thought to be close to the minimum size where they can remain effective. Graphene transistors can potentially run at faster speeds and cope with higher temperatures. Graphene could be the solution to ensuring computing technology to continue to grow in power whilst shrinking in size, extending the life of Moore’s law by many years” (Science Daily). In other words, graphene might be about to drop Jailhouse Rock.
Since scientists first isolated graphene in 2004, they’ve struggled to produce the carbon sheets in sizes large enough to be useful. Last year, a group led by University of Texas, Austin chemist Rodney Ruoff grew graphene squares one centimeter square atop flexible copper foils. A few days ago, a group of researchers led by Jong-Hyun Ahn and Byung Hee Hong of Sungkyunkwan University in South Korea submitted a report in Nature Nanotechnologydescribing their efforts to scale up the approach taken by the Texas team to make graphene sheets large enough for full-screen displays (Service).
The graphene microchip. (Credit: Photo / Donna Coveney)
Ahn and Hong et al used chemical vapor depositionto grow graphene on large sheets of copper foil. A thin adhesive polymer was layered on top of the graphene, and then the copper backing was dissolved away. “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)” (Service).
Credit: Jong-Hyun Ahn et al., Nature Nanotechnology, Advance Online Publication (2010).
Graphene could be used to make more efficient/cheaper solar cells, better large screen displays for electronics, and so on. If the larger sheet sizes pan out, we might just be looking at the Elvis of materials. Time will tell.
I’m filing graphene under EARTH because it’s carbon-based.
Science Daily. “Breakthrough in Developing Super-Material Graphene.” 01/19/10. Accessed 06/23/10. URL.
Service, Robert F. “Graphene Finally Goes Big.” Science Now. 06/20/10. Accessed 06/23/10. URL.