Swiss scientists demonstrate nanowire solar cell

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Scientists at École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland believe solar panels made from nanowires could be built with fewer materials and perform more efficiently than current photovoltaic modules.

Anna Fontcuberta i Morral and her team built a nanowire solar cell out of gallium arsenide, a material which is better at converting light into power than silicon. They found that it collects up to 12 times more light than the usual flat solar cell.

Fontcuberta’s prototype is said to be almost 10 per cent more efficient at transforming light into power than allowed, in theory, for conventional single material solar panels.

Furthermore, optimizing the dimensions of the nanowire, improving the quality of the gallium arsenide and using better electrical contacts to extract the current could increase the prototype’s efficiency.

The EPFL study, published in Nature Photonics, suggests that an array of nanowires may attain 33 per cent efficiency, whereas commercial (flat) solar panels are up to 20 per cent efficient.

Also, arrays of nanowires would use at least 10,000 times less gallium arsenide, allowing for industrial use of the material.