Engineering Self-Assembly of Nanoparticles into Chiral Superlattices Using Liquid-Phase TEM

Achieving chiral nanomaterials from nanoparticle self-assembly has attracted increasing attention due to their strong chiroptical activity and wide range of potential applications. Therefore, understanding the formation pathway at nanoscale is essential for precise chiral nanomaterial fabrication and engineering. Here, by using liquid-phase transmission electron microscopy (TEM) and theoretical interaction calculations based on coarse-grained models, we study the dynamics of chiral pinwheel superlattices formed by achiral tetrahedral gold nanoparticle self-assembly in solution. We show rapid nucleation and growth of low-density tetrahedral bilayer lattices from single particles. Chiral pinwheel superlattices ‘compressed’ from the low-density state at nanometer precision is experimentally realized by harnessing the energetics. Furthermore, diverse superstructures with variable domain sizes are achieved by engineering interparticle interactions and particle-substrate interactions simultaneously in real-time. Our study proposes a simple and versatile strategy to manufacture chiral and responsive nanomaterials based on the rich library of nanoparticles with unique optical, mechanical, and electronical properties.