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.