Professor
Andre Geim, who along with his colleague Professor Kostya Novoselov
won the 2010 Nobel Prize for graphene – the world's thinnest material,
has now modified it to make fluorographene – a one-molecule-thick
material chemically similar to Teflon.
The team
hope that fluorographene, which is a flat, crystal version of
Teflon and is mechanically as strong as graphene, could be used
as a thinner, lighter version of Teflon, but could also be in
electronics, such as for new types of LED devices.
Graphene,
a one-atom-thick material that demonstrates a huge range of
unusual and unique properties, has been at the centre of attention
since groundbreaking research carried out at The University
of Manchester six years ago.
Its potential
is almost endless – from ultrafast transistors just one atom
thick to sensors that can detect just a single molecule of a
toxic gas and even to replace carbon fibres in high performance
materials that are used to build aircraft.
Professor
Geim and his team have exploited a new perspective on graphene
by considering it as a gigantic molecule that, like any other
molecule, can be modified in chemical reactions.
Teflon is
a fully-fluorinated chain of carbon atoms. These long molecules
bound together make the polymer material that is used in a variety
of applications including non-sticky cooking pans.
The Manchester
team managed to attach fluorine to each carbon atom of graphene..
To get fluorographene,
the Manchester researchers first obtained graphene as individual
crystals and then fluorinated it by using atomic fluorine. To
demonstrate that it is possible to obtain fluorographene in
industrial quantities, the researchers also fluorinated graphene
powder and obtained fluorographene paper.
Fluorographene
turned out to be a high-quality insulator which does not react
with other chemicals and can sustain high temperatures even
in air.
One of the
most intense directions in graphene research has been to open
a gap in graphene's electronic spectrum, that is, to make a
semiconductor out of metallic graphene. This should allow many
applications in electronics. Fluorographene is found to be a
wide gap semiconductor and is optically transparent for visible
light, unlike graphene that is a semimetal.
Professor
Geim said: "Electronic quality of fluorographene has to be improved
before speaking about applications in electronics but other
applications are there up for grabs."
Rahul Nair,
who led this research for the last two years and is a PhD student
working with Professor Geim, added: "Properties of fluorographene
are remarkably similar to those of Teflon but this is not a
plastic.
"It is essentially
a perfect one-molecule-thick crystal and, similar to its parent,
fluorographene is also mechanically strong. This makes a big
difference for possible applications.
"We plan
to use fluorographene an ultra-thin tunnel barrier for development
of light-emitting devices and diodes.
"More mundane
uses can be everywhere Teflon is currently used, as an ultra-thin
protective coating, or as a filler for composite materials if
one needs to retain the mechanical strength of graphene but
avoid any electrical conductivity or optical opacity of a composite".
Industrial
scale production of fluorographene is not seen as a problem
as it would involve following the same steps as mass production
of graphene.
The Manchester
researchers believe that the next important step is to make
proof-of-concept devices and demonstrate various applications
of fluorographene.
Professor
Geim added: "There is no point in using it just as a substitute
for Teflon. The mix of the incredible properties of graphene
and Teflon is so inviting that you do not need to stretch your
imagination to think of applications for the two-dimensional
Teflon. The challenge is to exploit this uniqueness."
Contact: Daniel Cochlin
daniel.cochlin@manchester.ac.uk
0044-161-275-8387
University of Manchester
