There are a few things
about graphene that make it a fairly desirable material. First is its
ability to conduct electricity and it does so quite well. Research
into this property of graphene has made the future of flexible
electronics quite tantalizing.
Second is its strength as
compared to other substances on a molecular level. Graphene is 200
times stronger than steel, and the strongest of any material tested
at present. This property also makes it ideal for flexible
applications as the circuits constructed of graphene are much less
likely to break under distortion.
The only trouble with
graphene is until now it's been expensive or wasteful to produce.
Typically, graphite oxide would be rendered into graphene using
either high temperatures or toxic chemicals. While the heat treatment
is less problematic than the chemical variety, it still has some
drawbacks. If the chemists wanted to mix the graphene with another
substance, such as a polymer, the intense heat may destroy the other
substance. In the chemical treatment, the mixture substance could
prevent a reaction with the graphite oxide, making the technique
Jiaxing Huang, an assistant professor with
Northwestern's McCormick School of Engineering and Applied Science,
along with Rodolfo Cruz-Silva, a postdoctoral fellow, and Laura J.
Cote, a graduate student under Huang, may have, in a flash of
inspiration, made the former techniques obsolete. In fact, about the
only piece of modern technology necessary for Huang's process is an
ordinary camera flash.
Huang says of the process, “The light
pulse offers very efficient heating through the photothermal process,
which is rapid, energy efficient and chemical-free.” By simply
positioning the camera flash over graphite oxide and firing the bulb,
the substance is instantly reduced to graphene.
The process is
both incredibly simple and remarkably versatile. Not only does the
flash instantly transform the graphite oxide, it will also bond it to
an insulating polymer, creating a conducting composite.
approach is to etch a circuit design onto a sheet of overhead
transparency and use it as a mask. Similar to photo-lithography,
where the flash's intense light falls, the graphite oxide will be
converted to graphene while the dark areas will remain unchanged. The
beauty of this simple process is that while graphene is a great
electrical conductor, graphite oxide is the exact opposite – a
great electrical insulator. This produces, instantly, a precursory
Huang's group still has more planned to
improve the process. At present they have used only thick films in
their research, but intend to refine the technique in order to create
circuits on a single-atom sheet. A quick and easy micropatterning
system is not out of the realm of possibility.
Should a single
layer circuit printing process come about, manufacturers would simply
have to alternate layers of the circuit with layers of normal
graphite oxide or another single-atom, flexible insulator, and
inexpensive, flexible and durable electronic parts are right around
the corner. Some such electronic systems already exist, but they lack
the efficiency at manufacturing level that Huang's technique could
provide. It could be a boon for both military and consumer system
An excerpt of the Northwestern trio's work can be found