Ultraslim solar cells retain healthy efficiency

An ultrathin solar cell made of only a fifth of the material previous skinny devices have used to capture sunlight has shown that it still generates electricity impressively well. The gallium–arsenide (GaAs) based device made by researchers in Germany and France, led by Stéphane Collin at the Centre for Nanoscience and Nanotechnology in Paris, is 19.9% efficient. That’s in the range of today’s commercial silicon-based cells achieve, although this is just a small 4mm² research device.