To be clear, all light, visible and invisible, is radiation, and solar cells react to this radiation by producing an electric current.
Silicon solar cells, however, aren’t well-known for being reactive to infrared radiation, at least not very effectively. Silicon is an excellent choice for converting light in the visible spectrum to electricity, but outside of this band, the invisible long wavelengths of infrared light are pretty worthless when it comes to generating electricity. Actually, infrared wavelengths have proven to be a detriment to conventional silicon solar cell function because it heats up the connections, increasing resistance, reducing current flow.
A new kind of silicon solar cell was developed by researchers from Universitat Politècnica de Catalunya, Barcelona, Spain, under the direction of the Spanish National Research Council. The new solar cell is essentially wrapped around a silicon nanosphere. The nanosphere captures infrared light, redirecting it until the photovoltaic layer can use it to generate electricity.
The video, poasted by UPV Radiotelevisió, is in Spanish, so you might need to get a friend to translate, but it explains what the research team was working to accomplish.
No word yet on how much more efficient the new nanospherical silicon solar cell is, but taking advantage of this unused part of the spectrum will definitely be a boost.
Image © UPV Radiotelevisió (Screenshot)