Two-Dimensional Lead Halide Perovskites with Spirocyclic Intercalating Cations

Two-dimensional metal halide perovskites (TMHPs) are distinguished by their component-dependent material properties, and outstanding photophysical properties, positioning them as promising candidates for optoelectronic devices. Although numerous A-site cations have been integrated into TMHP scaffolds, only a few incorporate complex three-dimensional organic frameworks. Here we report the synthesis of five new TMHP single crystals incorporated with spirocyclic (SC) intercalating cations via a two-step synthetic approach. This method involves the formation of a thiazolidine-derived framework via condensation of zwitterionic ligands and cyclic ketones. Strong hydrogen bonding interactions between the ammonium termini of the SC ligands and the inorganic layers are observed in all the new TMHPs, drawing the SC cations closer to the [PbI6](4-) octahedra and stretching the heterocyclic scaffolds. Computational analyses reveal that the sulfur-containing SC ligands may significantly enhance the charge carrier mobility. These results demonstrate the potential of three-dimensional intercalating cation synthesis for the development of new perovskite-derived structures.