Solar cells made of thin, flexible materials are a sort of holy grail for the solar industry. Compared with today’s hard, heavy silicon based cells, they promise to be cheaper to manufacturer and easier to install. The problem, so far, is that they convert less sunlight into electricity than do conventional solar cells. Maybe not for much longer. According to the National Energy Renewable Labs, a new thin-film solar cell recipe (using copper indium gallium diselenide or CIGS) recently hit 19.9% efficiency, setting a new world record for this type of cell. Today’s multicrystalline silicon-based solar cells have shown efficiencies up to 20.3%. This is a lab success story, still far from a manufacturing breakthrough, but it suggests solar energy still has big potential to improve.