Fig. 3.
The perovskite composites remained stable under extremely intensive illumination. The solid and dashed lines are spectra obtained from experiments. The thin grey lines show the results of multiple-peak fitting. a–c Minimal changes were observed in the photoluminescence measured from the samples with XBr ≤ 0.6, even after 4 hours of illumination with intensity of 440 W cm−2. d–f The sample with higher bromine content (XBr ≥ 0.7), which was stable under low-intensity illumination, exhibited redshift and blueshift in the photoluminescence with the strong illumination (440 W cm−2)