In Situ Vapor-Phase Halide Exchange of Patterned Perovskite Thin Films.

Metal halide perovskites (MHPs) exhibit optoelectronic properties that are dependent on their ionic composition, and the feasible exploitation of these properties for device applications requires the ability to control the ionic composition integrated with the patterning process. Herein, the halide exchange process of MHP thin films directly combined with the patterning process via a vapor transport method is demonstrated. Specifically, the patterned arrays of CH NH PbBr (MAPbBr ) are obtained by stepwise conversion from polymer-templated PbI thin films to CH NH PbI (MAPbI ), followed by halide exchange via precursor switching from CH NH I to CH NH Br.