Novel Organic–Inorganic Perovskite Compounds Having Phosphonium Groups

[Image: see text] Organic–inorganic perovskites are composed of organic cations and [PbX(6)](4–) octahedra, and the properties change depending on the type of organic cations. To identify the effect of organic cations and control the properties of the perovskite, thin films were prepared using quaternary alkylammonium and quaternary alkylphosphonium cations, which have big steric effects. A big steric effect can generate the distortion of [PbX(6)](4–) octahedra leading to changes in properties. A thin film of a Pb-based organic–inorganic perovskite having quaternary alkylphosphonium cations was prepared for the first time. An exciton absorption was observed at a lower wavelength than other perovskites prepared from primary and quaternary ammonium salts. The perovskite with phosphonium groups was thermally stable compared with ammonium groups.