title: Investigation of CH3NH3PbI3 degradation rates and mechanisms in controlled humidity environments using in situ techniques.
abstract: Perovskite solar cells have rapidly advanced to the forefront of solution-processable photovoltaic devices, but the CH3NH3PbI3 semiconductor decomposes rapidly in moist air, limiting their commercial utility. In this work, we report a quantitative and systematic investigation of perovskite degradation processes. By carefully controlling the relative humidity of an environmental chamber and using in situ absorption spectroscopy and in situ grazing incidence X-ray diffraction to monitor phase changes in perovskite degradation process, we demonstrate the formation of a hydrated intermediate containing isolated PbI6(4-) octahedra as the first step of the degradation mechanism. We also show that the identity of the hole transport layer can have a dramatic impact on the stability of the underlying perovskite film, suggesting a route toward perovskite solar cells with long device lifetimes and a resistance to humidity.
authors: Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, SK Canada , S7N 5C9.
authors: Jinli
authors: J
authors: Yang
authors: Braden D
authors: BD
authors: Siempelkamp
authors: Dianyi
authors: D
authors: Liu
authors: Timothy L
authors: TL
authors: Kelly
keywords: GIXRD; decomposition; moisture; perovskites; relative humidity