Strontium Insertion in Methylammonium Lead Iodide: Long Charge Carrier Lifetime and High Fill-Factor Solar Cells.

The addition of Sr2+ in CH3 NH3 PbI3 perovskite films enhances the charge carrier collection efficiency of solar cells leading to very high fill factors, up to 85%. The charge carrier lifetime of Sr2+ -containing perovskites is in excess of 40 μs, longer than those reported for perovskite single crystals.