Competing formation of α and δ-FAPbI₃ in perovskite ink using 2-methoxyethanol as the solvent

2-Methoxyethanol (2-Me) is a promising solvent for large-area perovskite film preparation. Understanding the competing processes of α and δ-FAPbI₃ in 2-Me is crucial for advancing the application of 2-Me in FAPbI₃ film coating. In this study, FAPbI₃ microcrystals are fabricated by inverse temperature crystallization method at 100 °C, and are used as a platform to investigate the competing formation of α and δ-FAPbI₃ in 2-Me. Perovskite inks are analyzed using Raman, FTIR and DLS, and it is found that cluster ratio is closely related to the kinetic formation of δ-FAPbI₃. The formation of α-FAPbI₃ can be significantly promoted when clusters are dissociated with additives (excess FAI or I₂). These findings provide valuable insights into the influence of precursor inks on perovskite phases.