David Cahen

Perovskite (say it: pə-ˈräv-ˌskīt, -ˈräf-). It may never become a household word, and the chemical formulas (eg., CH3NH3PbI3−xClx ) are as long as the name. But if you find yourself, in the not-so-distant future, adding new-and-improved solar panels to your roof, they may well contain a perovskite layer. If they do, it will be these “wonder materials” that will make your panels cheap enough to make your investment worthwhile and efficient enough to make you feel smug when you get your electricity bill. You may ask: Aren’t solar panels dropping in price all the time? What is special…