A Strategy toward New Low-Dimensional Hybrid Halide Perovskites with Anionic Spacers

The low-dimensional halide perovskites have received enormous attention due to their unique photovoltaic and optoelectronic performances. Periodic spacers are used to inhibit the growth of 3D perovskite and fabricate a 2D counterpart with layered structure, mostly based on organic/inorganic cations. Herein, by introducing organic anions (e.g., pentanedioic acid (PDA) and hexanedioic acid (HDA) simultaneously), leaf-shaped (Cs₃ Pb₂ Br₅ )₂ (PDA-HDA) microplates with low-dimensional structure are synthesized. They also exhibit significant photoluminescence (PL) centered at 540 nm with a narrow emission peak. The synthesis of single crystals of Pb(PDA) and Pb(HDA) allows to further clarify the crystal structure of (Cs₃ Pb₂ Br₅ )₂ (PDA-HDA) perovskite and its structural evolution mechanism. Moreover, the cooperative introduction of dicarboxylic acid pairs with appropriate lengths is thermodynamically favored for the low-dimensional perovskite crystallization. The temperature-dependent PL indicates a V-shaped Stokes shift with elevated temperature that could be associated with the localization of excitons in the inorganic layers between organic dicarboxylic acid molecules. This work demonstrates low-dimensional halide perovskite with anionic spacers, which also opens up a new approach to the growth of low-dimensional organic-inorganic hybrid perovskite crystals.