Solar cells made from the mineral called perovskite are cheaper to make than conventional cells from silicon, but they haven’t been able to leave the lab without losing efficiency. Now a team of researchers from Brown University and the National Renewable Energy Lab (NREL) have solved that issue using a new method that makes perovskite solar cells larger and commercially viable. The new fabrication process is especially successful because the cells attained a 15% energy conversion efficiency, which the team believes they can improve another 5-10%, rivaling traditional solar cells. A cheaper, more efficient solar cell, now that’s music to the ears of an environmentalist.