Studying the Effect of Solvent Interactions in Fabricating High Purity 2D Perovskites for Optoelectronic Applications

2D perovskites have attracted attention due to their higher stability in comparison their 3D counterparts. However, attaining phase-pure 2D perovskites has been a challenge. Recently, our group showed an efficient way to make high phase purity (>95%) 2D Ruddlesden-Popper (RP) perovskite films that achieve solar cells with efficiencies greater than 17%. To extend our processing method to other 2D perovskites (Dion-Jacobson, alternating cation), a detailed study of solvent interactions with synthesized crystals/precursors is required. The solvent-3D perovskite interactions have been well studied to provide criteria for solvents that can produce high quality 3D perovskite films for solar cells. However, solvent interactions with the 2D perovskite are poorly understood. In this study, we investigate the influence of solvent dielectric constant, donor number, and Hansen parameter to predict interactions between 2D perovskite precursors/crystals and the solvent. We perform dynamic light scattering (DLS) correlated with microscopy, absorption, and GIWAXS measurements. Our initial results show a strong effect of various solvents on the 2D perovskites, building towards our end goal of fabricating phase-pure films of RP, DJ, and ACI for LED, and solar cells applications.