July 14, 2008
Window generates electricity
new device based on an older solar technology produces inexpensive
solar energy by capturing layers of light and concentrating them sideways.
The device is an update of a solar concentrator made from
a dye-infused sheet of plastic surrounded by ordinary solar cells.
In this older device light hits the plastic and is shunted sideways
into the solar cells. The new solar concentrator replaces the plastic
with glass that's coated with a transparent organic semiconductor
The transparent coating absorbs light and emits it at a different
wavelength. The new wavelength is shunted sideways through the glass
to the solar cells. Stack several concentrators that are tuned to
absorb different wavelengths of light and you can extract more energy
from the same sunlight.
The new device converts as much as 6.8 percent of the sunlight
that hits it to electricity. This is well below the 20 to 30 percent
conversion rate of more expensive silicon solar cells but 10 times
higher than older versions of the concentrator, and it's high enough
to be useful. The concentrators also doesn't need to be turned to
face the sun, which means they could be used as electricity-generating
windows in buildings.
Organic Solar Concentrators for Photovoltaics
Science, July 11, 2008
Soft Semiconductor Group, MIT
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