Metal Halide Perovskite Supercrystals: Gold-Bromide Complex Triggered Assembly of CsPbBr₃ Nanocubes

Using nanocrystals as "artificial atoms" to construct supercrystals is an interesting process to explore the stacking style of nanoscale building blocks and corresponding collective properties. Various types of semiconducting supercrystals have been constructed via the assembly of nanocrystals driven by the entropic, electrostatic, or van der Waals interactions. We report a new type of metal halide perovskite supercrystals via the gold-bromide complex triggered assembly of newly emerged attractive CsPbBr₃ nanocubes. Through introducing gold-bromide (Au-Br) complexes into CsPbBr₃ nanocubes suspension, the self-assembly process of CsPbBr₃ nanocubes to form supercrystals was investigated with the different amount of Au-Br complexes added to the suspensions, which indicates that the driven force of the formation of CsPbBr₃ supercrystals included the van der Waals interactions among carbon chains and electrostatic interactions between Au-Br complexes and surfactants. Accordingly, the optical properties change with the assembly of CsPbBr₃ nanocubes and the variation of mesoscale structures of supercrystals with heating treatment was revealed as well, demonstrating the ionic characteristics of CsPbBr₃ nanocrystals. The fabricated CsPbBr₃ supercrystal presents a novel type of semiconducting supercrystals that will open an avenue for the assembly of ionic nanocrystals.