Packing problems of tetrahedra is a long-standing research subject in math. In contrast its simplest shape, superstructures made from tetrahedra are complicated and intriguing. Self-assembly of tetrahedral nanocrystal building blocks into well ordered superstructures is a fundamental strategy for chemistry, however, it has not been well explored because of the difficulty in synthesizing a high-quality nanocrystals and the structural characterization. <br/>Here we report the packing of truncated tetrahedral quantum dots into four distinct superstructures—one-dimensional chiral tetrahelices, two-dimensional quasicrystal-approximant superlattices and three-dimensional cluster-based body-centred-cubic single supercrystals, and 10-fold quasicrystal superlattices—by controlling the assembly conditions. Characterization of the superstructures were conducted using techniques in real and reciprocal spaces, e.g. Synchrotron-based rotational X-ray scattering. We identified the structures from their nanocrystal translational orderings down to the atomic-orientation alignments of individual quantum dots. The selective facet-to-facet contact induced by the anisotropic patchiness of the tetrahedra were commonly found in the four superstructures, which is the key to facilitate such unusual self-assembling processes. This study provides information about the packing of non-spherical nanocrystals into complex superstructures, and may enhance the potential of self-assembled nanocrystal metamaterials in practical applications.

Self-assemblies of truncated tetrahedral quantum dots with anisotropic patchiness

2019 Fall National Meeting

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