Figure 1. Schematic illustration of the slip-coating process.

(a–c) and optical images extracted from a video of the growth of a set of slip-coated MAPbI₃ nanowires (d–f). SEM micrographs of a representative set of nanowires (g). AFM distribution of length and width of the set of nanowires shown in g. The liquid phase growth pattern is inherently determined by the formation of nucleation centers randomly distributed on the surface. The nanowires grow in dandelion-like pattern. The nanowires grow in radial direction out from the nucleation centers and form an assembly of crystallites that resembles a “paper fan”. We do see wire-wire intergrowth but we do not observe the formation of secondary bunches. The slip-coating process has no precise control over the dimensions of the as-synthesized nanowires.