Chiral Symmetry Breaking in Nanocrystal Superlattices Enabled by Shear and Nanowires.

The self-assembly of colloidal nanocrystals typically leads to the formation of highly symmetric superlattices, while chiral symmetry breaking within these structures remains rare. Here, we present a universal approach for achieving chiral symmetry breaking within self-assembled nanocrystal superlattices through the incorporation of nanowires and shear force. The networked film, composed of highly flexible nanowires that are only a few nanometers in diameter and bound by weak van der Waals interactions, can be manipulated to stretch and rotate, resulting in a controlled chiral pattern with a specified handedness. When combined with nanocrystal superlattices, the nanowires convey mechanical torque to the nanocrystals, inducing chiral symmetry breaking in the solid materials. This method is versatile and can be applied to various nanocrystal solids irrespective of their size, shape, or composition. Overall, this study enhances the repertoire of fabrication techniques for chiral nanomaterials, circumventing the need for chiral molecules.