Assembled Suprastructures of Inorganic Chiral Nanocrystals and Hierarchical Chirality

Chiral organizations ubiquitously exist in biomaterials via hierarchical assembly of chiral molecules, but assembly of chiral inorganic nanocrystals (NCs) has been lacking. Recent development of cinnabar HgS NCs that can possess precisely engineered chirality originating from both atomic lattice and morphology offers an emerging class of inorganic building blocks to explore their hierarchical assembly. Two different forms of suprastructures, collinear chains and propellers, have been achieved with various chiral HgS NC building blocks via distinct assembly mechanisms. The chiroptical responses of suprastructures are further evaluated both experimentally and theoretically, and are found to uniquely depend on intrinsic chirality of building blocks and their coupling. Our study therefore opens up a gateway to new assembled inorganic suprastructures with desired chiroptical response for wide-ranging functionalities and applications by bottom-up modular approach.