Degradation mechanism of planar-perovskite solar cells: correlating evolution of iodine distribution and photocurrent hysteresis

The penetration of moisture/O 2 into the perovskite solar cells (PSCs) causes shifts of iodine distribution within the perovskite layer and facilitates diffusion of iodine towards the hole transporting layer. Interestingly, these negative effects can be prevented by a simple encapsulation process and further prolong the stability of PSCs.