When you think of making antennas for radio communications, you probably think of metal wires. But researchers at the University of Manchester have figured out a way to make cheap antennas from the same material used in pencil lead.
The researchers use graphene, a sheet of carbon atoms linked into a lattice just one-atom thick. Instead of manufacturing metal wires, they print an antenna on paper using ink infused with graphene flakes, squashing it with a roller to increase how well it conducts electricity by a factor of 50.
That, in turn, could help spread network communications to a new class of cheap devices like clothing, thermometers and advertising posters at the bus station. It's the latest development involving a material that could revolutionize everything from computer chips to jet planes to solar panels to displays -- if scientists and engineers can just work around its difficulties.
Graphene has excited materials scientists since its 2003 discovery, when University of Manchester researchers managed to use simple Scotch tape to peel layers of exotic graphene off ordinary graphite, the form of carbon also used to make pencil lead. Isolating and characterizing graphene was momentous enough to earn the 2010 Nobel Prize in physics. That excitement stems from its unusual properties: it's stronger than steel, transparent and conducts electricity. But so far, graphene has been long on excitement and short on practical uses.
Graphene antennas could change that. As radio communications spread to millions of small devices -- everything from product tags in stores to pressure sensors in car tires -- there's a need for inexpensive, flexible antennas to carry the communication signals. Graphene could be the material that gives a voice to myriad new computing devices.
"Graphene is no longer just a scientific wonder. It will bring many new applications to our daily life very soon," said Kostya S. Novoselov, the project's coordinator and one of the University of Manchester Nobel Prize laureates who isolated graphene. He and fellow Nobel laureate Andre Geim are co-authors of the paper, but the lead author is graduate student Xianjun Huang.
Graphene has yet to meet its potential, though. Fans of the material hope it can be used for aerospace as a lighter, stronger replacement for carbon fibers; solar cells to generate electricity; flat-screen displays where its transparency and electrical conductivity is an asset; and perhaps most significantly, as athat could help sustain the pace of Moore's Law toward smaller, more powerful processors.
Researchers have tried printing electrical circuitry out of graphene before, but to get the ink to stick, the process used a binding material that doesn't conduct electricity. The binding material was removed through high-temperature processing that rules out plastic, paper, fabric and other cheap surfaces.
The University of Manchester researchers, along with colleagues from UK graphene manufacturer BGT Materials, describe a different approach in a paper published Thursday in the journal Applied Physics Letters. They dry the ink at a relatively low 100 degrees Celsius -- the boiling point of water -- then compress the ink with a roller it so it conducts electricity better.
"Graphene ink is very cheap," said Zhirun Hu, one of the researchers on the project. "The process to make graphene laminate with high conductivity is very simple and aimed for mass production."
One big use could be RFID -- radio-frequency identification tags pasted to products so stores can track their inventory, among other uses. Those tags today usually use aluminum and copper antennas, both relatively expensive metals.
"Graphene-based RFID tags can significantly reduce the cost thanks to a much simpler process and lower material cost," Huang said in a statement.
Printable graphene antennas could boost the graphene manufacturing industry, too, Hu said. And that, in turn, could help graphene adoption elsewhere. Graphene antennas are one practical use of the material, but more will come.
"The real applications are coming," he said.