Determination of multilevel chirality in nickel molybdate films by electron crystallography

Chiral inorganic materials have attracted great attention owning to their unique physical and chemical properties attributed to the symmetry-breaking of their nanostructures. Chiral inorganic materials can be endowed with chiral geometric configurations from achiral space group crystals through lattice twisting, screw dislocations or hierarchical self-assembled spiral morphologies, showing various characteristic chiral anisotropy. However, the multilevel chirality in chiral nickel molybdate films (CNMFs) remains to be elaborately excavated. In this paper, we report three hierarchical levels of chirality in CNMFs, spanning from the atomic to the micron scale, including primary helically coiled nanoflakes with twisted atomic crystal lattices, secondary helical stacking of layered nanoflakes, and tertiary asymmetric morphology between adjacent nanoparticles. Our findings may enrich the chiral self-assembly structural types and provide valuable insights for the comprehensive analysis path of hierarchical chiral crystals.