the fact that graphene has been known to exist for decades, only recently have researchers
begun to study graphene in earnest. The reason for the relatively late start
into research using grapheme is that the material was difficult to make in
quantities needed for research.
Once that hurdle was overcome, researchers quickly started to use graphene in
all manner of study for a variety of uses. Graphene is being studied for use in semiconductors as a
multiplier able to make processors many times faster than what we have access
to today. Researchers are still studying better and cheaper methods of making
grapheme and one important method was discovered in October
of 2009 for growing graphene.
A team of researchers at the University of Southern California has discovered a way to use graphene to produce
a flexible, printable sheet only four or less atoms thick. These graphene
sheets can then be bound to a flexible polymer sheet to create a new type of
organic photovoltaic cell or solar panel.
The resulting solar panel is thin and very flexible and the team believes that
the material may one day be used for creating clothing that can generate power
when worn in the sun. The big advantage of the graphene solar panel is that it
is very flexible, much more so than existing solar panel materials.
"Organic photovoltaic (OPV) cells have been proposed as a means to achieve
low cost energy due to their ease of manufacture, light weight, and
compatibility with flexible substrates," wrote Chongwu Zhou, a professor
of electrical engineering in the USC Viterbi School of Engineering, in a paper
recently published in the journal ACS Nano.
The team creates the flexible graphene sheets needed for the solar panels by
chemical vapor deposition. Carbon atoms are deposited in the form of graphene
films onto a nickel plate from a methane gas. After the molecules are
deposited, a thin protective layer of thermo plastic covers them. After the
protective layer is deposited, the nickel plate is dissolved in an acid bath.
The left over film is very flexible and can be incorporated into an OPV. The
downside to an OPV compared to a traditional solar panel made of silicon is
that the OPV is able to convert less solar radiation into electricity.
every 1000 watts of sunlight that hits a one square meter area of the standard
silicon solar cell, 14 watts of electricity will be generated," says Lewis
Gomez De Arco, a doctoral student and a member of the team that built the
graphene OPVs. "Organic solar cells are less efficient; their conversion
rate for that same one thousand watts of sunlight in the graphene-based solar
cell would be only 1.3 watts."
The team thinks that in the future these OPV sheets could be made into a fabric
that could be hung like curtains or worn as clothing that can generate power.
Another interesting use would be to cover the seats in an electric car or
hybrid with the material to help capture power for the vehicles battery