The Stability of Organochalcogenide-Halide Perovskites with Covalently Attached A-Site Cations

We recently described a synthetic strategy for incorporating chalcogenides into the framework of halide perovskites through the use of organochalcogenides (RCh where R = organic group and Ch = S and Se). In particular, we used zwitterionic organochalcogenides terminating with an ammonium group (⁺NH₃RCh^-) to replace the A⁺ site and one of the X^- sites in the ABX₃ perovskite leading to A sites that are covalently bound to the inorganic framework. Our initial studies on these organochalcogenide-halide perovskites ((CYS)PbX₂ and (SeCYS)PbX₂; CYS = ⁺NH₃(CH₂)₂S^-, SeCYS = ⁺NH₃(CH₂)₂Se^- X = Cl^- or Br^-) showed improved stability to the all-halide analogs and a notable reduction in ionic mobility, assessed through 2D NMR measurements. I will present our recent studies on this new family of perovskites, emphasizing the unusual structural and electronic consequences of the attached A site and its restricted motion within the perovskite cubeoctahedral cavity.