Solution Properties of 2D Ruddlesden–Popper Perovskites

We report a quantitative experimental platform to investigate the role of solvent on two-dimensional (2D) Ruddlesden–Popper (RP) halide perovskite (HaP) dissolution properties and thin film quality based on Hansen solubility parameters (HSPs). We find that the particle size and particle size distributions are dependent on the HaP structure and HSP number. We then investigate the thin film properties of 2D RP structures using absorption spectroscopy and X-ray diffraction (XRD) as a function of the HSP number. We observe that solvents with a low HSP number result in thin films with high phase purity and desired out-of-plane orientation. In contrast, we show that solvents with a high HSP number result in thin films with poor phase purity, low excitonic peak intensities, and undesired in-plane orientation. Our study shows the importance of understanding the molecular interactions that drive dissolution and thin film formation of perovskite structures, which is critical for optimizing processing conditions during scale-up.