Efficiency record for black silicon solar cells jumps to 22.1%

The researchers have obtained the record-breaking efficiency of 22.1% on nanostructured silicon solar cells as certified by Fraunhofer ISE CalLab. An almost 4% absolute increase to their previous record is achieved by applying a thin passivating film on the nanostructures by Atomic Layer Deposition, and by integrating all metal contacts on the back side of the cell.

The surface recombination has long been the bottleneck of black silicon solar cells and has so far limited the cell efficiencies to only modest values. The new record cells consists of a thick back-contacted structure that is known to be highly sensitive to the front surface recombination. The certified external quantum efficiency of 96% at 300nm wavelength demonstrates that the increased surface recombination problem no longer exists and for the first time the black silicon is not limiting the final energy conversion efficiency.

The development of the cells fabricated last year will continue in the upcoming “BLACK” project in which Professor Savin together with her team will develop the technology further in cooperation with industry.

Nature Nanotechnology - Black silicon solar cells with interdigitated back-contacts achieve 22.1% efficiency

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