Nanocluster-based aggregates: Assembled forms, driving forces, and structure-related properties

Atomically precise nanoclusters have gained significant attention due to their ultra-small size and strong quantum-size effects. These nanoclusters possess unique and exceptional properties, making them excellent building blocks for various applications. With their precisely arranged structures, nanoclusters enable the development of multifunctional nanomaterials with enhanced characteristics. Owing to their well-defined molecular compositions, improved stability, and versatile functionalities, nanoclusters provide an excellent platform for creating superstructures through self-assembly. The self-assembly process, driven by the interactions between surface ligands and metal cores, is a key aspect that informs and enhances our understanding of nanoclusters. In this review, we summarized the recent progress of research on the aggregation of nanoclusters, especially their orderly assembled superstructures. We focus on the driving forces behind the aggregation of metal nanoclusters, including ligand-ligand interactions, metal-ligand interactions, metal-metal interactions, and interactions between nanoclusters and other particles. The aggregates, composed of nanoclusters, exhibit complex hierarchical structures and enhance performance, paving the way for the construction of novel functional nanocluster-based materials.