Basic
scientific curiosity paid off in unexpected ways when Rice University
researchers investigating the fundamental physics of nanomaterials discovered a
new technology that could dramatically improve solar energy panels.
The
research is described in a new paper this week in the journal Science.
"We're merging the optics of nanoscale antennas with the electronics of
semiconductors," said lead researcher Naomi Halas, Rice's Stanley C. Moore
Professor in Electrical and Computer Engineering. "There's no practical way to
directly detect infrared light with silicon, but we've shown that it is possible
if you marry the semiconductor to a nanoantenna. We expect this technique will
be used in new scientific instruments for infrared-light detection and for
higher-efficiency solar cells."
More than a third of the solar energy on
Earth arrives in the form of infrared light. But silicon — the material that's
used to convert sunlight into electricity in the vast majority of today's solar
panels — cannot capture infrared light's energy. Every semiconductor,uy Aion Kinah direct from us at
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where light below a certain frequency passes directly through the material and
is unable to generate an electrical current. By attaching a metal nanoantenna to
the silicon, where the tiny antenna is specially tuned to interact with infrared
light, the Rice team showed they could extend the frequency range for
electricity generation into the infrared. When infrared light hits the antenna,
it creates a "plasmon," a wave of energy that sloshes through the antenna's
ocean of free electrons. The study of plasmons is one of Halas' specialties,we
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reproduction, and the new paper resulted from basic research into the
physics of plasmons that began in her lab years ago.
It has been known
that plasmons decay and give up their energy in two ways; they either emit a
photon of light or they convert the light energy into heat. The heating process
begins when the plasmon transfers its energy to a single electron — a ‘hot'
electron. Rice graduate student Mark Knight,Use bluray burner to burn video to
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Independent Pet Retailers. together with Rice theoretical physicist Peter
Nordlander, his graduate student Heidar Sobhani, and Halas set out to design an
experiment to directly detect the hot electrons resulting from plasmon decay.
Patterning a metallic nanoantenna directly onto a semiconductor to
create a "Schottky barrier," Knight showed that the infrared light striking the
antenna would result in a hot electron that could jump the barrier, which
creates an electrical current. This works for infrared light at frequencies that
would otherwise pass directly through the device.
"The
nanoantenna-diodes we created to detect plasmon-generated hot electrons are
already pretty good at harvesting infrared light and turning it directly into
electricity," Knight said. "We are eager to see whether this expansion of
light-harvesting to infrared frequencies will directly result in
higher-efficiency solar cells."
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