Draw a line with a pencil and it’s likely that somewhere along that black smudge is a material that earned two scientists the 2010 Nobel Prize in Physics. The graphite of that pencil tip is simply multiple layers of carbon atoms; where those layers are only one atom thick, it is known as graphene.
The properties of a material change at the nanoscopic scale, making graphene the strongest and most conductive substance known. Instead of marking mini-golf scores on paper, this form of carbon is suited for making faster and smaller electronic circuitry, flexible touchscreens, chemical sensors, diagnostic devices, and applications yet to be imagined.
Graphene is not yet as ubiquitous as plastic or silicon, however, and producing the material in bulk remains a challenge. Because graphene’s properties rely on it being only one atom thick, until recently, it was only possible to make it in small patches or flakes.
Physicists at Penn have discovered a way around these limitations, and have spun out their research into a company called Graphene Frontiers.
Graphene Frontiers’ technology was developed by A.T. Charlie Johnson, director of Penn’s Nano/Bio Interface Center and a professor in the Department of Physics and Astronomy in Penn Arts & Sciences, along with Zhengtang Luo, a former postdoctoral researcher in Johnson’s lab. They founded the company in 2011 through the Penn Center for Innovation’s UPstart program, which serves as a business incubator for technologies developed at the University. UPstart connected the researchers with Michael Patterson, then a member of the Wharton Executive MBA program, and now the company’s CEO.
Graphene Frontiers’ approach advances a process known as chemical vapor deposition, where a carbon-rich gas similar to methane reacts with a surface in an oven, leaving behind its carbon atoms in an even sheet. The company’s technique for polishing the deposition surface to an atomic smoothness allows the process to take place in atmospheric conditions, rather than the vacuum usually necessary, meaning it can be more easily integrated with other industrial techniques. Graphene Frontiers is currently scaling up to go from making meter-long sheets to a production process reminiscent of newspaper printing.
“A roll of copper foil goes in to the growth system, and a roll of graphene on a suitable backing comes out,” says Johnson, who is also the chair of Graphene Frontiers’ scientific advisory board. “This sort of ‘roll-to-roll’ process would enable large-scale production of graphene with high quality at low cost.”
One of the applications the founders are most excited about is based on Johnson’s research connecting biological components to graphene. Those components naturally bind to specific molecules in their environment; attaching them to graphene enables them to serve as ultra-sensitive chemical detectors that could be used to monitor pollution or diagnose diseases. A cellular receptor, or an immune system agent such as an antibody that normally alerts the body to the presence of a certain molecule, would instead drive an electrical response that could be read out on a computer.
“Graphene serving as the key component allows us to make a diagnostic tool that is multiplexed,” Patterson says. “With a single drop of blood, your physician would be able to test for dozens, even hundreds, of different things and have results within minutes.”