PHOTOS BY JONATHAN CHAPMAN
Current solar cells, like the one held here by Professor Eray
Aydil, are usually made of silicon that require high
temperatures and vacuum processing during production, all
of which increase the cost. Aydil and his team are researching
ways to apply nanotechnology to produce lower-cost, high-efficiency
solar cells.
Aydil and other researchers study how the nanowire-based solar
cell (above) absorbs different colors of sunlight and generates
electricity.
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Institute
of Technology Professor Eray Aydil (chemical engineering and materials
science) is not only undertaking research that could make solar-powered
electricity inexpensive enough to compete against coal, natural
gas and other fossil-fuels that currently drive the nation's electrical
grid, he's helping to lay the foundation for breakthroughs by the
next generation.
Aydil is researching ways to apply nanotechnology to solar-voltaic
cells, which convert sunlight into electrical energy that can be
stored for future use.
Currently, solar cells must be constructed from very high-grade
materials—usually silicon—that require high temperatures and vacuum
processing during production, all of which increase the cost. During
production, conventional cells are doped with impurities that absorb
light and convert it into positive and negative currents.
“We are aiming at architectures that are much less expensive,” Aydil
said.
To achieve that goal, Aydil and his fellow collaborators, professors
Uwe Kortshagen (mechanical engineering), David Norris (chemical
engineering and materials science), and Xiaoyang Zhu (chemistry),
are following two different, though related tracks. Both rely on
nanotechnology.
One kind of solar cell they are developing employs nanowires coated
with a light-sensitive dye; the other uses light-sensitive quantum
dots, or nanoparticles, attached to nanowires. “The advantage of
nanowires is that they have large surface areas and so can absorb
a lot of dye or contain lots of dots that can convert sunlight into
an electrical current,” Aydil explained, the other big advantage
is cost. The architecture of both the dye-sensitized and quantum-dot
cells is much simpler than conventional solar voltaic cells and
potentially much easier to produce, Aydil said.
“Essentially everything is done in a beaker in a lab,” Aydil said.
“That could vastly reduce the cost of solar cells.” And that, in
turn, would speed the day when the sun becomes a major source of
electricity to meet the world's growing demand for clean power.
In addition to Aydil's solar research in the lab, he's also helping
bright young students reach their potential. This year, he volunteered
to mentor a team of Hopkins junior high students participating in
the FIRST LEGO League robotics competition, which focused on nanotechnology.
The team won the Division II state championship for their presentation
on nano-based solar cells and will represent the state at the World
LEGO League Festival in Atlanta this spring.
“I hope the junior high students I mentored this year will come
to research and study with me at the U in a few years,” Aydil said.
The University currently has 150 graduate students and post-docs,
including nearly 75 Ph.D. candidates, who are focusing their studies
in renewable energy.
“At the University of Minnesota , we're not just researching renewable
energy, we're training the workforce for tomorrow's renewable energy
industry.”
By Richard Broderick
Excerpted with permission from the article “Energy Alternatives”
in the Spring/Summer 2007 issue of Inventing
Tomorrow, the magazine of the University of Minnesota Institute
of Technology.
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