Chenjie Zeng1
University of Florida1
Chiral semiconductor nanostructures have potential applications in chiral optoelectronics, spintronics, sensors, and catalysis. Compared to organic molecules, the origins of chirality in semiconductor nanomaterials are less understood due to many possible chiral geometries at hierarchical levels. Here, we unveil the intrinsic origins of chirality in II-VI semiconductor nanoclusters by achieving atomic precision in a tetrahedral-shaped CdSe nanocluster and X-ray crystallographic analysis. We show that the chirality emerges from the incorporation of tetrahedral coordination of individual ions into the icosahedral packing of the lattices, breaking the symmetry of the inorganic core from an achiral <i>I</i><sub>h</sub> to a chiral <i>T</i>. The chirality in the CdSe core further propagates to the metal-ligand interface, as manifested in the clockwise and counter-clockwise rotations of the interfacial coordination patterns. The asymmetric assembly of ligands on the tetrahedral facets further breaks the cluster symmetry from <i>T</i> to <i>C</i><sub>3</sub>. The left- and right-handed enantiomers are co-crystallized as a 1:1 racemic mixture. The resolved atomic structure of the chiral CdSe clusters shed light on the chiral structures observed in the larger semiconductor nanocrystals and their assemblies.