Ternary Phase Diagrams of MAI–PbI2–DMF and MAI–PbI2–DMSO Systems

In this study, we thoroughly measured the joint solubility of MAI and PbI2 components in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvents at different temperatures and analyzed the composition of solid phases in equilibrium with the saturated solutions to build phase diagrams for the two ternary systems of MAI–PbI2–DMSO and MAI–PbI2–DMF. A new solvate phase MAI·DMSO was discovered in the system MAI–PbI2–DMSO, and its crystal structure has been refined. Based on the obtained data, we compared and analyzed phase equilibria in these two systems. The diagrams give ground fundamental information on the ternary systems and explain how the solution composition influences the crystallization process and determines phase composition of the products and possible pathways of crystallization of hybrid perovskites.