Fig. 1. (a) Schematic illustration of the synthesis process with varying DMSO concentrations to achieve either (002) or (200) facet alignment in a precursor solution containing 1.875 mmol mL⁻¹ PbAc₂ and 5.625 mmol mL⁻¹ MAI. (b–d) Schematic illustrations (left) of the different crystal facets parallel to the substrate, representing the main orientation deducted from 2D GIWAXS data (middle) and the SEM images of the respective films (right). (b) Perovskite film with the (002) facet parallel to the substrate; (c) perovskite film with (200) and (321) facets parallel to the substrate; (d) perovskite film with the (200) facet parallel to the substrate.