Understanding the mechanism of metal-induced degradation in perovskite nanocrystals.

A deeper understanding of the perovskite-metal chemistry is crucial to elucidate the instability problems at the device level that can be caused by such interactions. Here, we study the reactions occurring between CsPbX3 (X = Br, BrI, I) perovskite and metal (M = Ag, Cu, Au) nanocrystals. We demonstrate a fast (<1 hour) optical and structural degradation of the I-containing nanocrystals driven by the formation of metal iodides with reaction kinetics according to the following order Cu < Ag < Au. These results point to the need for thoughtful considerations while constructing optoelectronic devices out of all-inorganic CsPbX3 nanocrystals, where the use of contact metals is a necessity.