April 8, 2013
Nanowires May Mean More Efficient, Cheaper Solar Panels
Enid Burns for redOrbit.com — Your Universe Online
Nanowires could be the answer for constructing solar panels with less materials and lower costs. Researchers at the Ecole Polytechnique Federale De Lausanne (EPFL) are working on new technology to advance solar panels.
New research on tiny filaments called nanowires has made some promising findings. Influenced by nature, researcher Anna Fontcuberta i Morral looked at how trees in a forest stand upright to collect energy from the sun. She is developing a system, inspired by forests, that stands nanowires up on a panel. The new structures are able to capture large quantities of light and produce energy with greater efficiency than current panels, and at a lower cost.
While the nanowires are small in size, they provide potential for energy products. "These nanowires capture much more light than expected," said Fontcuberta.
Nanowires are extremely tiny filaments with a diameter that measures tens of hundreds of nanometers. A nanometer is one millionth of a millimeter. Nanowires are up to 1,000 times smaller than the diameter of human hair. They are comparable in diameter to the size of viruses, the report said.
Researchers have found that when equipped with the right electronic properties, the nanowire becomes a tiny solar cell. It transforms sunlight into electric current.
A nanowire solar cell was built by Fontcuberta and her team out of gallium arsenide, a material that works to convert light into power, similar to silicon. The group found that the material collects up to twelve times more light than a flat solar cell, which translates into more collected energy.
"The nanowire standing vertically essentially acts like a very efficient light funnel," the report said. "Even though the nanowire is only a few hundred nanometers in diameter, it absorbs light as though it were twelve-times bigger. In other words, it has a greater field of vision than expected."
[ Watch the Video: Nanowires Have the Power to Revolutionize Solar Energy ]
A prototype solar panel using nanowire was found to be ten percent more efficient at transforming light into power, compared to conventional single-material solar panels. The new panel optimizes the dimensions of the nanowire, which improves the quality of gallium arsenide and better uses electrical contacts to extract the current.
New solar panels made from nanowire and gallium arsenide have several advantages. "The study suggests that an array of nanowires may attain 33 percent efficiency, in practice, whereas commercial (flat) solar panels are now only up to 20 percent efficient. Also, arrays of nanowires would use at least 10,000 times less gallium arsenide, allowing for industrial use of this costly material. Translating this into dollars for gallium arsenide, the cost would only be $10 per square meter instead of $100,000," the report finds.
Solar panels made with this new concept could be less expensive and use fewer materials. They might also weigh less, which means less of a load placed on rooftop installations.
"Free to the engineer´s imagination to mount these nanowires onto a variety of substrate panels, be it lightweight, flexible or designed to withstand the harshest of conditions. In a world where energy consumption is on the rise, these nanowires may one day power everything from your favorite gadget to space missions to Mars," the report said.