Probing the Degradation Chemistry and Enhanced Stability of 2D Organolead Halide Perovskites.

Recent work on quasi-2D Ruddlesden-Popper phase organolead halide perovskites has shown that they possess many interesting optical and physical properties. Most notably, they are significantly more stable when exposed to moisture when compared to the typical 3D perovskite methylammonium lead iodide (MAPI); direct evidence for the chemical source of this stability remains elusive, however. Here, we present a detailed study of the superior moisture stability of a quasi-2D Ruddlesden-Popper perovskite, -butylammonium methylammonium lead iodide (nBA-MAPI), compared to that of MAPI, and examine a simple, yet efficient, methodology to improve the stability of MAPI devices through the application of a thin layer of nBA-MAPI to the surface.