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.