New Organic–Inorganic Perovskite Materials with Different Optical Properties Modulated by Different Inorganic Sheets

New organic–inorganic perovskites with different PbBr perovskite sheets stabilized by 3- or 4-amidinopyridine were synthesized and structurally characterized. 4-Amidinopyridine constructs <001>-oriented perovskite with inorganic sheets made up of typical corner-sharing octahedra of PbBr2. Analogous chemistry in the presence of 3-amidinopyridine under the same conditions results in an unusual hybrid perovskite with the inorganic sheets showing a novel framework including both corner-sharing and edge-sharing PbBr2, which is different from any previously reported ones. Fine thin films were obtained through a spin-coating process which offers the compounds potential photoelectric application. Optical properties investigation for the two compounds revealed different absorption excitonic peaks of hybrid perovskites at 399 and 411 nm, respectively, which can be attributed to their different inorganic sheets. Band structures of the compounds were calculated by the CASTEP code based on density functional theory.