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Revisiting a once-abandoned technique, engineers at the Massachusetts
Institute of Technology (MIT) have successfully created a
sophisticated, yet affordable, method to turn ordinary glass
into a high-tech solar concentrator.
The technology, which uses dye-coated glass to collect and
channel photons otherwise lost from a solar panel's surface,
could eventually enable an office building to draw energy
from its tinted windows as well as its roof.
Electrical engineer, Marc Baldo, his graduate students Michael
Currie, Jon Mapel and Timothy Heidel and postdoctoral associate
Shalom Goffri, announced their findings in the July 11 issue
of Science. "We think this is a practical technology
for reducing the cost of solar power" - said Baldo.
The researchers coated glass panels with layers of two or
more light-capturing dyes. The dyes absorbed incoming light
and then re-emitted the energy into the glass, which served
as a conduit to channel the light to solar cells along the
panels' edges. The dyes can vary from bright colours to chemicals
that are mostly transparent to visible light.
Because the edges of the glass panels are so thin, far less
semiconductor material is needed to collect the light energy
and convert that energy into electricity.
"Solar cells generate at least ten times more power when
attached to the concentrator" - added Baldo.
Because the starting materials are affordable, relatively
easy to scale-up beyond a laboratory setting and easy to retrofit
to existing solar panels, the researchers believe the technology
could find its way to the marketplace within three years.
The new technology emerged in part from an NSF Nanoscale
Interdisciplinary Research Team effort to transfer the capabilities
of photosynthesis to solar technology.
The researchers' approach succeeded where efforts from the
1970s failed, because the thin, concentrated layer of dyes
on glass is more effective than the alternative - a low concentration
of dyes in plastic - at channelling most of the light all
the way to the panel edges. However, the current technology
still needs further development to create a system that will
last the 20 to 30-year lifetime necessary for a commercial
product.
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