Fabrication of two-dimensional hybrid organic–inorganic lead halide perovskites with controlled multilayer structures by liquid-phase laser ablation†
Organic–inorganic hybrid lead halide perovskites are the most promising class of materials that have attracted considerable attention for usage in photovoltaic materials, light-emitting materials, and other photonics applications. In addition to the most actively investigated lead halide perovskites with three-dimensional (3D) bulk films and crystals, a wide variety of lower-dimensional hybrid halide perovskites have been developed. Two-dimensional (2D) perovskites with a stacking structure composed of metal halide nanosheets and organic cations exhibit variations in their electronic structures and optoelectronic properties owing to their high degree of freedom in designing multilayer structures. In this study, a one-step synthesis of 2D layered lead bromide perovskites by laser ablation of a 3D perovskite target in an organic solvent is demonstrated. Alkylamine addition to the solvent before the commencement of ablation successfully produced periodic multilayer structures assembled from monolayer sheets of lead bromide octahedra and alkylamines in the interlayer space. The 2D lead-bromide perovskites exhibited characteristic blue emission from quantum-confined excitons in the monolayer sheets. Interlayer spacings were well controlled between 1.3–3.5 nm by appropriate selection of alkyl chain length of the amine additives. These results may offer a new route to fabricate novel functional compounds constructed using metal halide perovskite layers and intercalated optically active molecules using a simple method.