Solar panels suffer from two fundamental problems that have continued to persists even after decades of research: they’re not very efficient, and they cost a lot to produce. At least one of these problems has to be solved beforesolar power can overtake cheap energy sources like fossil fuels, and some scientists have had their hopes pinned on a common mineral called perovskite. This is an organometal with peculiar light-absorbing properties, and a team of researchers from the University of Sheffield say they’ve figured out how to create high-efficiency perovskite solar cells with a spray painting process. Yes, spray-on solar panels might actually happen.