Solar power is getting much, much better. Now, a team of scientists has created the world’s most efficient nano-structured black silicon solar cell—which converts an impressive 22.1 percent of incident light into electricity.
The team, from Finland’s Aalto University and Universitat Politècnica de Catalunya, have smashed the existing record for such a cell by four per cent. When a photon hits the surface of a PV cell, it causes a quantum reaction that spits out an electron. The researchers boosted the efficiency by adding a new layer to the back surface of the cell, which encourages those electrons to flow through as electricity rather than recombining with the photovoltaic materials at the surface. The results are published online in Nature Nanotechnology.
While black silicon solar cells don’t yet provide the highest efficiencies of PV solar cells, their deep black colour makes them well-suited to generating electricity when the sun is low in the sky, as they absorb more light than other cells. “This is an advantage particularly in the north, where the sun shines from a low angle for a large part of the year,” explains Professor Hele Savin to PhysOrg. “We have demonstrated that in winter Helsinki, black cells generate considerably more electricity than traditional cells even though both cells have identical efficiency values.”
No PV cell can compare to what’s claimed to be the new most efficient solar power system, which manages a terrific 34 per cent efficiency. But there’s still a place for PV cells, as they can be more easily positioned on buildings in built-up areas, unlike solar farms. Now, the team hopes to create the new black silicon solar cells at industrial scale. [Nature Nanotechnology via PhysOrg]
Image by Aalto University