Performance Enhancement of Perovskite Solar Cells Induced by Lead Acetate as an Additive

The crystallinity of organic–inorganic hybrid lead halide perovskite active layers is critical to the performance of perovskite solar cells (PSCs). However, it is a challenge to control the crystallization process of perovskite films by solution process. Here, the fabrication of high-efficiency PSCs by employing lead acetate (PbAc₂) as an additive in the perovskite precursor is demonstrated for the first time. By adding a few percent of PbAc₂ (molar ratio with respect to PbI₂) into the precursors, the perovskite crystallization process is significantly retarded, leading to pinhole-free perovskite films with large grains and low defect densities. As result, the power conversion efficiencies and stability of the PSCs are substantially improved. This work provides a convenient and unique approach for preparing high-quality perovskite films that can be used in photovoltaics as well as other optoelectronic devices.