A team of scientists at Massachusetts Institute of Technology (MIT) have come up with what they are calling a “solar funnel,” a discovery that could vastly improve the efficiency of future types of photovoltaic (PV) cell solar energy systems.
The team, headed by MIT Associate Professor of Chemical Engineering, Michael Strano, hopes that by using nanotechnology to create hollow tubes of carbon atoms which capture and concentrate solar energy – up to 100 times more than regular solar cells – along their length, it will be possible to build vastly more powerful solar energy systems, but which take up less space than current types of rooftop PV systems on the market.
“Instead of having your whole roof be a photovoltaic cell, you could have little spots that were tiny photovoltaic cells, with antennas that would drive photons into them,” Professor Strano says.
Solar panels generate electricity by converting photons captured from sunlight into an electric current. Strano’s nanotube antenna boosts the number of photons that can be captured and transforms the light into energy that can be funneled into a solar cell.
By manipulating the miniscule layers of nanotube fibres that make up the solar funnels, Strano’s team has pioneered the ability to control the flow and intensity of electrons through the antennas, from inner layer to outer, ultimately striking another material (like a solar cell) in an excited, and therefore more concentrated, state.
Boosting the generation capacity of traditional photovoltaic cells using carbon nanotube technology would become a cheap and efficient alternative to silicon solar arrays, according to Strano.
“At some point in the near future, carbon nanotubes will likely be sold for pennies per pound, as polymers are sold,” he says.
“With this cost, the addition to a solar cell might be negligible compared to the fabrication and raw material cost of the cell itself, just as coatings and polymer components are small parts of the cost of a photovoltaic cell.”
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Image credit: Geraldine Paulus
