Removing the lead hazard from perovskite solar cells

Although a very promising solution for capturing solar energy, perovskite solar cells contain lead, which is toxic to the environment and a serious health hazard. scientists have now found a very elegant and efficient solution by adding a transparent phosphate salt that doesn't interfere with light-conversion efficiency while preventing lead from seeping into the soil in cases of solar panel failure. "The solar energy-to-electricity conversion of perovskite solar cells is unbelievably high, around 25%, which is now approaching the performance of the best silicon solar cells," says Professor László Forró at EPFL's School of Basic Sciences. "But their central element is lead, which is a poison; if the solar panel fails, it can wash out into the soil, get into the food chain, and cause serious diseases." The problem is that in most of the halide perovskites lead can dissolve in water. This water solubility and solubility in other solvents is actually a great advantage, as it makes building perovskite solar panels simpler and inexpensive - another perk along with their performance. But the water solubility of lead can become a real environmental and health hazard when the panel breaks or gets wet, e.g. when it rains. So the lead must be captured before it gets to the soil, and it must be possible to recycle it.