High-performance photovoltaic perovskite layers fabricated through intramolecular exchange

Taking in more sun Most efforts to grow superior films of organic-inorganic perovskites for solar cells have focused on methylammonium lead iodide (MAPbI 3 ). However, formamidinium lead iodide (FAPbI 3 ) has a broader solar absorption spectrum that could ultimately lead to better performance. Yang et al. grew high-quality FAPbI 3 films by starting with a film of lead iodide and dimethylsulfoxide (DMSO) and then exchanging the DMSO with formamidinium iodide. Their best devices achieved power conversion efficiencies exceeding 20%. Science , this issue p. 1234