Researchers are the first to develop a solar cell with good efficiency that uses tin instead of lead perovskite as the harvester of light. The low-cost, environmentally friendly solar cell can be made easily using 'bench' chemistry -- no fancy equipment or hazardous materials. Perovskite solar cells are being touted as the 'next big thing in photovoltaics.' Lead perovskite has achieved 15 percent efficiency, and tin perovskite should be able to match -- and possibly surpass -- that.