Companies say they are close to commercializing cheap perovskite films that could disrupt solar power — but are they too optimistic?
The Henn na hotel in Nagasaki, Japan, is not shy of trialling futuristic technology. It claimed to be the world’s first robot-staffed hotel in 2015 — but cut down on the automation after its robotic concierges frustrated some customers and didn’t reduce costs. Now, the Henn na is testing another attention-grabbing innovation: since December, its sign has been powered by a curved wall of prototype solar cells installed in the hotel’s grounds. Made by Polish start-up firm Saule Technologies, the cells exploit micrometre-thin films made from materials called perovskites, which in just a decade have shot from laboratory curiosity to bright new prospect for solar power.
Japan is not the only place where perovskite-containing solar cells have ventured outside labs in the past 18 months. Saule has hung them high on an office building near its headquarters in Warsaw; a leading British firm in the sector, Oxford PV, is testing them at a pilot production site in Brandenburg an der Havel, Germany; and the Chinese firms Microquanta Semiconductor and WonderSolar have been running field tests in the cities of Hangzhou and Ezhou. More than a dozen companies worldwide (see ‘Solar hopes’), a mixture of established electronics giants and start-ups, are hoping soon to sell panels made with perovskites. Dozens more are involved in making materials for the products, says Margareth Gagliardi, an analyst with BCC Research in Wellesley, Massachusetts.
For decades, slabs of crystalline silicon have dominated the solar industry. Other materials that can be layered in thin films, such as copper indium gallium selenide (CIGS) and cadmium telluride (CdTe), have captured less than 5% of the market, because it’s hard to make them as efficient or cheap as conventional solar panels. Perovskites could be a different story. They should be cheaper to make and seem impressively efficient at converting sunlight into electricity — in the laboratory, at least.