In DepthMaterials Science

Solar cell built for two looks sweet

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Science  12 Apr 2019:
Vol. 364, Issue 6436, pp. 116
DOI: 10.1126/science.364.6436.116

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Standard rooftop silicon solar cells are better at converting reddish hues of sunlight to electricity than bluer ones. So companies are racing to top silicon cells with another photovoltaic made from cheap, crystalline materials called perovskites, which excel at grabbing the blues. But crafting two solar cells, one atop the other, brings added costs, among other challenges. Now, researchers report they've advanced a simpler, and potentially cheaper way to make a tandem solar cell. They've spiked a conventional lead-based perovskite with yttrium. The resulting film doesn't turn sunlight to electricity. Rather, it absorbs blue and purple photons and re-emits that energy as near-infrared light, which the silicon cell then converts to electricity. The new tandem, researchers say, could increase the electrical output of silicon cells by close to 20%, a major boost.