Nanowires can Increase Efficiency of Solar Cells: Researchers

Researchers have found that a single nanowire can concentrate about 15 times higher-than-normal sunlight intensity. The latest findings on nanowires show that the material can be used in the field of solar power generation.

There is a limit to the maximum efficiency of a solar cell as described by the Shockley-Queisser limit. The SQ limit is applicable to about 99.9 percent of all solar cells sold in the market. The new discovery means the SQ limit can be increased; which can, in the future, lead to more efficient solar cells.

Peter Krogstrup, an author of the study, said that the properties of nanowires extend the limit of light absorption from the sun's rays, making them a good candidate to be used in solar cells. The study team developed the nanowire crystals that have a diameter which is roughly equivalent to 10,000^th part of human hair. These nanowires don't just find applications in solar cells, but can also be used to improve the efficiency of quantum computers and other electronic devices.

"It turns out that the nanowires naturally concentrate the sun's rays into a very small area in the crystal by up to a factor 15. Because the diameter of a nanowire crystal is smaller than the wavelength of the light coming from the sun it can cause resonances in the intensity of light in and around nanowires. Thus, the resonances can give a concentrated sunlight, where the energy is converted, which can be used to give a higher conversion efficiency of the sun's energy," said Peter Krogstrup, according to a news release from the Niels Bohr Institute, University of Copenhagen.

Krogstrup added that it will take some years for the nanowires to become part of commercially available solar cells.

The discovery was made by researchers from Nano-Science Center at the Niels Bohr Institut, Denmark, and the Ecole Polytechnique Fédérale de Lausanne, Switzerland.

The study is published in the journal Nature Photonics.