Low-cost solar cells poised for commercial breakthrough

Low-cost solar cells poised for commercial breakthrough

Cheap materials called perovskites are insinuating themselves into silicon solar cells—a first step toward ultimately usurping the reigning cell material. Last week, at a meeting here of the Materials Research Society (MRS), researchers announced that “tandem” cells, in which perovskites are layered on top of silicon and other photovoltaic materials, have achieved record-setting efficiencies at turning sunlight into electricity. Now, researchers are moving fast to surmount the lack of durability and other problems that have hindered the commercialization of perovskites.

“I think perovskites are going to make it to market,” says Aslihan Babayigit, a perovskite researcher at Hasselt University in Diepenbeek, Belgium. The progress has been “amazing,” adds David Cahen, a materials scientist at the Weizmann Institute of Science in Rehovot, Israel. “Even if all the problems are not solved, most look solvable.”

Known since the 1830s, perovskites are a class of crystals with a common 3D structure. It wasn’t until 2009 that researchers in Japan first realized their potential as a photovoltaic material. The first perovskite devices converted only 3.8% of light energy into electricity, far less than crystalline silicon, today’s dominant commercial technology, which tops out at 25.3% efficiency for the best research cells. (Commercial cells usually vary between 16%–20%.) But researchers tinkered with their perovskite recipes, and the efficiencies of the cells quickly skyrocketed. The record now stands at 22.1%, demonstrated earlier this year by researchers in South Korea.

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