Abstract
Beneficial effects are demonstrated by PbI2 incorporated into perovskite materials as a light absorber in solar cells. The PbI2 distributed into the perovskite layers leads to reduced hysteresis and ionic migration, and enables the fabrication of remarkably improved solar cells with a certified power conversion efficiency of 19.75% under air‐mass 1.5 global (AM 1.5G) illumination of 100 mW cm−2 intensity.