A new method allowing graphene production at room temperature could pave the way for wider commercialisation of the wonder material including manufacturing of solar cells and flexible electronics.
Developed by researchers at the California Institute of Technology (Caltech), the method allows the one-atom thick layer of carbon to be deposited onto surfaces of a much larger square area than was previously possible.
"With this new technique, we can grow large sheets of electronic-grade graphene in much less time and at much lower temperatures," said Caltech staff scientist David Boyd, the author of the method.
So far, to make a few square millimetres of electronic-grade graphene, extremely high temperatures of up to 1,000 degrees Celsius were necessary. The traditinal method also required a longer period of time and multiple steps.
"Our new method can consistently produce high-mobility and nearly strain-free graphene in a single step in just a few minutes without high temperature,” said Caltech physics professor Nai-Chang Yeh. “We have created sample sizes of a few square centimetres, and since we think that our method is scalable, we believe that we can grow sheets that are up to several square inches or larger, paving the way for realistic large-scale applications."
Graphene, isolated for the first time in 2003 by Manchester University researchers Andre Geim and Konstantin Novoselov, is hailed for its exquisite properties. Two hundred times stronger than steel and allowing electrons to travel across its surface two to three orders of magnitude faster than silicon, graphene is widely believed to be the next big thing in electronics.
The researchers say that producing graphene at low temperatures would not only cut manufacturing costs but also result in higher quality material as the high temperatures frequently cause defects. Tests on graphene manufactured with the new 'cool' method proved the material is not only stronger but also offers an even higher electrical mobility than that achieved with previously developed methods.
The new technique, described in the latest issue of Nature Communications, uses a system developed in the 1960s to generate hydrogen plasma. The researchers said they had discovered the method completely by accident when one of the engineers accidently left a sheet of copper foil in the apparatus for longer after having been distracted by a phone call.
The team believes scaling up the process could open the door for new kinds of electronics manufacturing. According to Professor Yeh, graphene sheets with low concentrations of defects could be used to protect materials against degradation from exposure to the environment or allow manufacturing of ultra-thin solar panels and displays.
"In the future, you could have graphene-based cell-phone displays that generate their own power," Yeh said.