Graphene isn't just for mobile phones, researchers at the Institute of Photonic Sciences found. Although Nokia is exploring the material for its potential in making smaller and faster electronics, it has endless implications for solar energy. Compared to the materials that make up the majority of solar panels today, such as silicon and gallium arsenide, graphene is far more efficient.
Silicon solar panels can convert one photon to one electron, but the amount of energy contained in a photon far exceeds the amount that an electron can hold — solar cells operate at around 30 percent efficiency. Graphene is made of a honeycomb network of carbon molecules. It is the thinnest and lightest material known to man — and when exposed to photons, it can convert it to multiple electrons. In Frank Koppens's research, he found that graphene could theoretically convert photons with about 60 percent efficiency.
Koppens came to this conclusion after blasting two light pulses at a single layer of graphene — the first would send a predetermined amount of energy into a layer of graphene and the second would measure the number of electrons that result.
The professor told TechnologyReview that the most immediate impact graphene would have is in the field of image sensing, and his lab is already working on a prototype for use in camera sensors, medical sensors and night vision goggles. Its implications for uses in solar panels is still a little way off, mostly because of engineering limitations.
Graphene-powered solar cells would probably be part of a third-generation wave of solar cells, which refers to a setup that incorporates technology that has not yet been developed.
Andrea Ferrari, a professor of nanotechnology at the University of Cambridge tells TechnologyReview that he had conducted a similar experiment, still unpublished but with a similar conclusion. He said that graphene can "work with every single possible wavelength you can think of," and that it is a durable, relatively cheap material that can be easily integrated with other materials.
