Investigation of CH3NH3PbI3 degradation rates and mechanisms in controlled humidity environments using in situ techniques

ACS Nano. 2015 Feb 24;9(2):1955-63. doi: 10.1021/nn506864k. Epub 2015 Feb 9.

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.

Keywords: GIXRD; decomposition; moisture; perovskites; relative humidity.

Publication types

  • Research Support, Non-U.S. Gov't