Figure 2. Structural characterization of the perovskite films deposited on c-TiO₂-coated FTO substrates using CVD method:

(a) XRD patterns of FTO, TiO₂ film on FTO substrate (the peaks labeled with “*” are from TiO₂), CH₃NH₃PbI_3-xCl_x and CH₃NH₃PbI₃; (b) top-view secondary electron SEM image of a CH₃NH₃PbI_3-xCl_x layer, with an inset showing backscattered electron (BSE) image with higher resolution; (c) cross-sectional BSE SEM image of a CH₃NH₃PbI_3-xCl_x layer; (d) AFM height images (10 × 10 μm) with an inset showing 3D topographic image.