Solar-powered energy collected by panels made of silicone is limited — contemporary panel technology can only convert approximately seven percent of optical solar waves into electric current. Researchers at Tel Aviv University are now working to develop a more efficient solar panel composed of nano-antennas instead of semiconductors. By adapting classic metallic antennas to absorb light waves at optical frequencies, a much higher conversion rate from light into usable energy could be achieved.
For optimal absorption, the antenna dimensions must correspond to the light’s very short wavelength — a challenge in optical frequencies that plagued engineers in the past, but now it is possible to fabricate antennas less than a micron in length.
The researchers believe these “old school” antennas also have greater potential for solar energy because they can collect wavelengths across a much broader spectrum of light. The solar spectrum is very broad, with UV or infrared rays ranging from 10 microns to less than 200 nanometers. No semiconductor can handle this broad a spectrum, and they absorb only a fraction of the available energy. A group of antennas, however, can be manufactured in different lengths with the same materials and process, exploiting the entire available spectrum of light.
When finished, the team’s new solar panels will be large sheets of plastic that, with the use of a nano-imprinting lithography machine, will be imprinted with varying lengths and shapes of metallic antennas.
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Also: Using nanoparticle “inks” developed at University of Texas at Austin, “paintable” solar cells could be printed more cheaply.
