Antisolvent Crystallization Approach to Construction of CuI Superstructures with Defined Geometries

A facile high-yield production of cuprous Iodide (CuI) superstructures is reported by antisolvent crystallization using acetonitrile/water as a solvent/antisolvent couple under ambient conditions. In the presence of trace water, the metastable water droplets act as templates to induce the precipitation of hollow spherical Cul superstructures consisting of orderly aligned building blocks after drop coating. With water in excess in the mixed solution, an instant precipitation of Cul random aggregates takes place due to rapid crystal growth via Ion-by-ion attachment induced by a strong antisolvent effect. However, this uncontrolled process can be modified by adding polymer polyvinyl pyrrolidone (PVP) In water to restrict the size of initially formed Cul crystal nuclei through the effective coordination effect of PVP. As a result, Cul superstructures with a cuboid geometry are constructed by gradual self-assembly of the small Cul crystals via oriented attachment. The precipitated Cul superstructures have been used as competent adsorbents to remove organic dyes from the water due to their mesocrystal feature. Besides, the Cul superstructures have been applied either as a self-sacrificial template or only as a structuring template for the flexible design of other porous materials such as CuO and TiO2. This system provides an ideal platform to simultaneously Investigate the superstructure formation enforced by antisolvent crystallization with and without organic additives.