Layered Perovskite-like Nitrate Cs2Pb(NO3)2Br2 as a Multifunctional Optical Material

A novel alkali metal lead halide nitrate, Cs2Pb(NO3)2Br2, has been successfully synthesized via a hydrothermal method. Interestingly, the title compound features a distinctive Ruddlesden–Popper perovskite-like layered structure, which induces the outstanding multifunctional optical properties, including a large birefringence (0.147@546 nm) and broad light-orange emission. Detailed structural analysis and theoretical calculations revealed that the large birefringence originates from the p−π interaction between the Pb2+ cations and NO3 groups and that the excellent luminescence properties derive from the distortion of PbO4Br4 polyhedra. This work not only enriches the variant structure types of layered perovskites but also guides the further exploration of all-inorganic multifunctional optical materials.