Perovskites, salt-like crystals that dissolve rapidly in water or even high humidity, have been used in experimental solar cells for some time,

But design breakthroughs have boosted efficiencies to a record 21%, making the technology competitive with market-dominating CSi, and cadmium-telluride and copper-indium-gallium-selenide thin-film, which have efficiencies of 17-23%.

"While the efficiency question has been answered, there remain issues in stability, cost, and the feasibility of real-world efficiencies that must be addressed before commercialisation can occur," says Lux Research associate Tyler Ogden.

"Still,