Chiral Symmetry\nBreaking in Nanocrystal Superlattices\nEnabled by Shear and Nanowires

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