Figure 4

SEM images of (a) fresh and (b) aged triple cation perovskite absorber on FTO/TiO2. The exposure to ambient conditions included 10 days of storage in a petri dish/at 25 °C and RH ~ 30 to 40%. SEM images of (c) fresh and (d) aged MAPbI3 perovskite absorber on FTO/TiO2. The fresh and aged triple cation appeared to be more dense compared to the MAPbI3 whose porosity increased with aging leading to potential avenues for nucleating degradation mechanisms.