Thermal Stability of 2D/3D Halide Perovskites

Halide perovskite solar cell stability is a major topic of research for the field and has explored intrinsic material stability, device architecture, and packaging. Efforts at improving halide perovskite material stability have recently seen success with mixed dimensionality, or 2D/3D, halide perovskites where a long-chain ammonium cation can be added to the material and improve thermal stability and moisture resistance. In this report, we explore a series of long-chain ammonium cations and investigate their effects on the thermal stability of methylammonium lead iodide films. We see that even small changes in the long-chain cation structure can lead to significant thermal stability differences, even when only small amounts of this cation are added to the perovskite thin films. This work helps to uncover thermal degradation mechanisms in mixed 2D/3D halide perovskites, and should lead to more thermally stable perovskite solar cells.