Degradation of inverted architecture CH3NH3PbI3-xClx perovskite solar cells due to trapped moisture

We explore degradation pathways within encapsulated CH3NH3PbI3-xClx perovskite devices based on the inverted architecture: ITO/PEDOT:PSS/CH3NH3PbI3-xClx/PC70BM/LiF/Al. Devices were subjected to more than 670 h of continuous illumination approximating AM1.5, with a Ts80 lifetime of (280 ± 20) hours determined. Devices stored in the dark underwent a similar drop in efficiency over the same time-period. Using external quantum efficiency, time-resolved photoluminescence, X-ray diffraction, scanning electron microscopy and laser beam induced current mapping, we attribute the primary cause of degradation to reactions with residual moisture trapped in the device, resulting in the decomposition of the perovskite.