FAPbI₃ Powder Synthesis Routes for State‐of‐the‐Art Perovskite Solar Cells: A Review

Formamidinium‐rich perovskite compositions are frontrunners in commercializing perovskite solar cells (PSCs), enabling record efficiency and stability. Conventionally, the fabrication of perovskite films involves the deposition of perovskite inks prepared by mixing individual precursor components (such as formamidinium iodide and lead iodide) in a solvent mixture. However, preparing these precursor mixtures often introduces deviations in the final composition due to impurities in the precursors, nonstoichiometric weighing of reagent, the presence of unreactive species, or the formation of nonperovskite phases. These deviations can significantly impact device efficiency, stability, and batch‐to‐batch reproducibility. In recent years, there has been increasing interest in presynthesized perovskite powders as a starting material for preparing perovskite inks. This approach offers improved reproducibility and photovoltaic performance in PSCs by mitigating nonstoichiometry issues while simplifying the complexity of solution preparation. Herein, a detailed review of the various chemical synthesis routes for preparing formamidinium‐rich perovskite powders is presented, highlighting their impact on powder quality and the resulting influence on photovoltaic performance and stability.