Supramolecular Assembly of Halide Perovskite Building Blocks

The structural diversity and tunable optoelectronic properties of halide perovskites originate from the rich chemistry of the metal halide ionic octahedron [MX₆]^n- (M = Pb²⁺, Sb³⁺, Te⁴⁺, Sn⁴⁺, Pt⁴⁺, etc.; X = Cl^-, Br^-, and I^-). The properties of the extended perovskite solids are dictated by the assembly, connectivity, and interaction of these octahedra within the lattice environment. Hence, the ability to manipulate and control the assembly of the octahedral building blocks is paramount for constructing new perovskite materials. Here, we propose a systematic supramolecular strategy for the assembly of [MX₆]^n- octahedra into a solid extended network. Interaction of alkali metal-bound crown ethers with the [M(IV)X₆]^2- octahedron resulted in a structurally and optoelectronically tunable "dumbbell" structural unit in solution. Single crystals with diverse packing geometries and symmetries will form as the solid assembly of this new supramolecular building block. This supramolecular assembly route introduces a new general strategy for designing halide perovskite structures with potentially new optoelectronic properties.