A team of U.S researchers have developed a new nanomaterial that when applied to the surface of solar cells absorbs light from across the entire spectrum, a breakthrough that could lead to more efficient solar panels.
Under the leadership of Koray Aydin, an assistant professor of electrical engineering and computer science from the McCormick School of Engineering, the team used metal and silicon oxide to create a unique and specific trapezoid-shaped grating on the nano-scale level. While the materials on their own do not absorb light, when combined in this manner and configuration, it results in a “broadband” light-capture effect.
As Aydin explains: “The solar spectrum is not like a laser – it’s very broadband, starting with UV and going up to near-infrared. To capture this light most efficiently, a solar cell needs to have a broadband response. This design allows us to achieve that.”
It does so by using the trapezoid grate structure create an “optical resonance” effect, which traps light for inside the material until it is absorbed. The structure is also able to collect light from many different angles.
The ability to absorb many different wavelengths of light from all sides would mean a solar cell could keep converting sunlight into electricity at close to full efficiency throughout the day, even as the sun rises and sets.
However, in a paper published in the journal Nature Communications, the researchers point out that they have yet to apply their findings to solar cell technology. Unfortunately, metal and silicon oxide are unable to convert light into electricity – instead they turn photons into heat.
But it is the innovative trapezoid-shape grating design which could lead to better solar efficiencies in the future. Aydin says that by by replicating the light-absorbing structure using semiconducting materials, the technology could lead to thinner, lower-cost, and more efficient solar cells.
