Researchers at the Massachusetts
Institute of Technology are seeking to increase the efficiency
of solar cells by helping them take advantage of more of the
MIT scientists are testing solar cells with a layer of
carbon nanotubes that “make it possible to take advantage of
wavelengths of light that ordinarily go to waste,” according to
a statement yesterday from the Cambridge, Massachusetts-based
Standard polysilicon photovoltaic cells don’t “respond”
to the entire spectrum of sunlight, limiting the amount of
photons they’re able to convert into electricity. Scientists
have said standard polysilicon has a theoretical maximum
efficiency of 33.7 percent. The nanotube technology may be used
to surpass that limit, according to Evelyn Wang, an MIT
associate professor of mechanical engineering.
Cell efficiency, the amount of energy in sunlight that’s
converted into electricity, “could ideally be over 80
percent,” she said in the statement.
MIT scientists combined carbon nanotubes, hollow cylinders
with walls that are one-atom thick, with photonic crystals to
create an “absorber-emitter.” When the nanotubes absorb
concentrated sunlight, their temperature rises, heating the
device to as much as 962 degrees Celsius (1,763 degrees
Just as a red-hot iron glows in a fire, the heated crystals
emit light that the photovoltaic cell is able to turn into
electricity, according to the statement.
The most efficient standard cells in production today
convert about 22 percent of sunlight energy into electricity.
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