Degradation observations of encapsulated planar CH3NH3PbI3 perovskite solar cells at high temperatures and humidity

Abstract

The stability of encapsulated planar-structured CH₃NH₃PbI₃ (MAPbI₃) perovskite solar cells (PSCs) was investigated under various simulated environmental conditions. The tests were performed under approximately one sun (100 mW cm⁻²) illumination, varying temperature (up to 85 °C cell temperature) and humidity (up to 80%). The application of advanced sealing techniques improved the device stability, but all devices showed significant degradation after prolonged aging at high temperature and humidity. The degradation mechanism was studied by post-mortem analysis of the disassembled cells using SEM and XRD. This revealed that the degradation was mainly due to the decomposition of MAPbI₃, as a result of reaction with H₂O, and the subsequent reaction of hydroiodic acid, formed during MAPbI₃ decomposition, with the silver back contact electrode layer.