Enhancing the planar heterojunction perovskite solar cell performance through tuning the precursor ratio

The presence of excess PbI₂can affect the structure of perovskites and photovoltaic performance of perovskite solar cells. Increased open-circuit voltage could be achieved by introducing proper PbI₂. However, shorter carrier lifetime and increased recombination and resistance were observed when an excess of PbI₂was used.