Scientists from the Barcelona Institute of Photonic Sciences (ICFO), in collaboration with German and American researchers, have just demonstratedgraphene is capable of converting an absorbed photon into multiple electrons that can conduct electrical current. This promising discovery makes graphene an important alternative for solar energy technology, currently based on conventional semiconductors such as silicon.Nature Physics.
“In most materials, an absorbed photon generates a single electron, but in the case of graphene we have seen that an absorbed photon is capable of producing many excited electrons, and therefore a larger electrical signal,” explains Frank Koppens, leader. of the research group at ICFO. This feature makes granadathe ideal brick for the construction of any device that wants to convert light into electricity. In particular, it enables the production of potential solar cells and light detectors that absorb the sun’s energy with much lower losses.
The experiment consisted of sending a known number of photons at different energies onto a thin layer of graphene. “We have seen that high-energy photons – for example, those of violet color – induce a greater number of excited electrons than low-energy photons – for example, infrared ones -“, clarifies Klass-Jan Tielrooij, also a researcher at ICFO .
Although it was already known that graphene is capable of absorbing a very large spectrum of colors from light, it is the first time that it has been shown that, once the material has absorbed this light, the energy conversion efficiency is very high. “Our next challenge will be to find ways to extract the electric current and improve the absorption of graphene.. Then we will be able to design graphene devices that give way to more efficient solar cells “announces Koppens. Not surprisingly, everything seems to indicate that in the coming decades aparadigm shift with graphene similar to what happened with plastic last century. Mobiles that fold, electronic paper, windows that are at the same time transparent solar panels, pots and pans that warn if there are any bacteria in food and other devices may be developed in the not too distant future with graphene, one of the most important materials. thin, flexible, strong and with higher conductivity created so far.
