Fig. 13

(Top) schematic illustrate of the vapor assisted solution process (VASP) and (bottom) XRD and SEM images of the perovskite thin film obtained by annealing PbI₂ film (~200 nm) in the presence of MAI vapor at 150 °C in N₂ atmosphere. a XRD patterns of the film annealed at 0, 0.5, and 4 h, b–d plane-view SEM images of b the initial stage at 0 h, c the intermediate stage at 0.5 h (inset wider view, scale bar 3 μm), and d the post stage at 4 h. Reprinted with permission from Ref. [53]