John Toon
Research News
When residents of New York’s Manhattan
Island ran out of real estate for new construction,
they expanded
vertically — using multi-story buildings to get
more living space on their compact island.
Scientists
at the Georgia
Tech Research Institute (GTRI) hope
to follow their example, but on a nanometer scale — building
carbon nanotube towers atop photovoltaic (PV) cells
to extract more power from the sun.
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GTRI
scientists have demonstrated an ability to
precisely grow “towers” composed
of carbon nanotubes atop silicon wafers. The work
could be the basis for more efficient solar power.
This image was taken at a 20 micron — or
20,000 nanometer — scale. |
The nanometer-scale
towers, which would be coated by the special semiconductor
junction materials used to
generate electrical current, would increase the
surface area available to produce electricity.
Reflections off the towers would
provide more opportunity for each photon of sunlight
to interact with the semiconductor junction of the
cell. That would
increase the power output from PV cells of a given size, or allow cells to
be made smaller while producing the same amount of power.
“You will typically get low voltages from the
sun, but it generates a steady-state supply — like
a fuel cell — but without the need for a consumable
fuel,” explained Jud Ready, a research engineer in GTRI’s Electro-optics,
Environment and Materials Laboratory who is the project’s principal
investigator. “It
would certainly be viable for recharging and for supplying power to a base
where people are stationed long-term. This could have significant benefits
from a supply
logistics standpoint.”
The three-dimensional cells could be useful in
space applications, where power is in constant demand and launch weight
is critical. Ultimately, they
also
could be used in developing nations where low-cost electrical power is
vital to expanding
economies.
The researchers have already developed techniques
for precisely growing carbon nanotube bundles atop
silicon wafers
that have been treated with
catalysts
to produce geometries that resemble three-dimensional nano-models of
Manhattan.
The next step will be to work with collaborators
at GTRI and the Schools of Materials Science and
Engineering and Electrical and Computer Engineering
to
apply the
special coatings, whose junction produces current.
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