content: It all comes down to how photovoltaic materials work in general. When a photon of incoming light strikes the active material – usually silicon – it knocks an electron out of one of its atoms. But under certain circumstances, one high-energy photon could bump two electrons out, without violating any laws of physics. It goes without saying that tapping into that phenomenon could be extremely helpful for improving the design of solar cells. In many photovoltaic materials efficiency is lost in several ways, including photons being reflected away from the device, or electrons recombining with the “hole” they left in the atom before they can be collected by the circuit. But the Aalto team says it’s largely removed these barriers. Black silicon absorbs far more photons than other materials, and the cone and column nanostructures reduce electron recombination at the surface of the material. Together, these advances made for a device with 130-percent external quantum efficiency. The team even had these results independently verified by the German National Metrology Institute, Physikalisch-Technische Bundesanstalt (PTB).  ...