Fig. 2

Perovskite films processed from precursors with different component ratios. a–d XRD patterns (a), light-intensity-dependent PLQEs (b), PL decays (c) and SEM images (d) of thermal annealed perovskite films processed from precursors with different x values (x = 1.5, 2.0, 2.5 and 3.0). The scale bars in the SEM images are 1 µm