a time when oil prices are reaching record highs
and people are bracing for winter heating bills,
researchers at Wake Forest University's Center for
Nanotechnology and Molecular Materials have made
significant strides in improving the efficiency of
organic or flexible solar cells.
Traditional silicon solar panels are heavy and bulky
and convert about 20 percent of the light that hits
them to useful electrical power. For years, researchers
have worked to create flexible, or "conformal," organic
solar cells that can be wrapped around surfaces,
rolled up or even painted onto structures, but the
best scientists have been able to do is about 3 percent
efficiency, until now.
Researchers at Wake Forest, with the help of researchers
at New Mexico State University, have achieved an
efficiency rate for organic solar cells of almost
6 percent. In order to be considered a viable technology,
the solar cells must be able to convert about 10
percent of the energy in sunlight to electricity.
Wake Forest researchers hope to reach 10 percent
by October 2006, said David Carroll, director of
the nanotechnology center at Wake Forest.
"The consumer market would be really open to having
these conformal systems if you could, for instance,
roll them up and put them away," said Carroll, who
is also an associate professor in Wake Forest's physics
department. "Imagine a group of hikers with a tent
that when you unrolled the tent and put it up, it
could generate its own power. Imagine if the paint
on your car that is getting hot in the sun was instead
converting part of that heat to recharge your battery."
Carroll said flexible, organic solar cells also
offer several possibilities for military use.
"The military would obviously want something like
that because you could only put maybe tens of those
big solar panels on a transport, but you could put
hundreds of ultra-thin flexible ones on a transport
and supply half the army," he said.
Most experts have estimated that flexible, solar
cell technology for consumers was about a decade
away, but Carroll said the new breakthrough at Wake
Forest and NMSU means that consumers could be using
this technology in the next five years.
Using a set of polymer coatings, researchers at
Wake Forest constructed a nanophase within the polymer
called a "mesostructure." The "mesostructure" changes
the properties of the plastic and makes it better
for collecting light. The researchers also removed
the current from the polymer coating, Carroll said.
A test system at Wake Forest's nanotechnology center
was used to simulate the sun, Carroll said, and the
simulated spectrum was precisely measured and shot
onto the organic solar cell, which appeared as a
thin coat of paint. Devices at the center have registered
almost 6 percent efficiency.
This breakthrough was announced in October at the
Santa Fe Workshop on Nanoengineered Materials and
Macro-Molecular Technologies, which was sponsored
by Wake Forest's nanotechnology center.
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