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takyon writes:

Researchers at Aalto University and the Universitat Politècnica de Catalunya have created black silicon (silicon with nanopatterned "needles" on the surface, lowering the reflectivity) solar cells with an efficiency of 22.1%. Their research is published in Nature Nanotechnology. These solar cells can capture more light than traditional cells with the same efficiency:

"The energy conversion efficiency is not the only parameter that we should look at" explains Professor Hele Savin from Aalto University, who coordinated the study. Due to the ability of black cells to capture solar radiation from low angles, they generate more electricity already over the duration of one day as compared to the traditional cells.

"This is an advantage particularly in the north, where the sun shines from a low angle for a large part of the year. We have demonstrated that in winter Helsinki, black cells generate considerably more electricity than traditional cells even though both cells have identical efficiency values," she adds.

In the near future, the goal of the team is to apply the technology to other cell structures – in particular, thin and multi-crystalline cells.

"Our record cells were fabricated using p-type silicon, which is known to suffer from impurity-related degradation. There is no reason why even higher efficiencies could not be reached using n-type silicon or more advanced cell structures." Hele Savin predicts.

The development of the cells fabricated last year will continue in the upcoming "BLACK" project, supported by the European Union, in which Professor Savin together with her team will develop the technology further in cooperation with industry.

"The surface area of the best cells in the study was already 9 cm². This is a good starting point for upscaling the results to full wafers and all the way to the industrial scale."