Fig. 8

(Top) schematic illustration of the FDC process and conventional spin-coating process for fabricating perovskite films. In the FDC process, a second solvent (e.g. chlorobenzene) introduced on top of the wet MAPbI₃ film during the spin-coating process induces fast crystallization of uniformly sized perovskite grains. a, b Low- and high-magnification SEM plane-view images and c high-resolution TEM image of a MAPbI3 film prepared by FDC with the addition of chlorobenzene. d, e Low- and high-magnification SEM images of a film prepared by conventional spin-coating without using anti-solvent. f XRD patterns for the films for FDC method and conventional spin-coating method. Reprinted with permission from Ref. [46]