The assembly of uniform nanocrystal building blocks into well ordered superstructures is a fundamental strategy for the generation of meso- and macroscale metamaterials with emergent nanoscopic functionalities1–10. The packing of spherical nanocrystals, which frequently adopt dense, face-centred-cubic or hexagonal-close-packed arrangements at thermodynamic equilibrium, has been much more widely studied than that of non-spherical, polyhedral nanocrystals, despite the fact that the latter have intriguing anisotropic properties resulting from the shapes of the building blocks11–13. Here we report the packing of truncated tetrahedral quantum dot nanocrystals into three distinct superstructures—one-dimensional chiral tetrahelices, two-dimensional quasicrystal-approximant superlattices and three-dimensional cluster-based body-centred-cubic single supercrystals—by controlling the assembly conditions. Using techniques in real and reciprocal spaces, we successfully characterized the superstructures from their nanocrystal translational orderings down to the atomic-orientation alignments of individual quantum dots. Our packing models showed that formation of the nanocrystal superstructures is dominated by the selective facet-to-facet contact induced by the anisotropic patchiness of the tetrahedra. 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.Truncated tetrahedral nanocrystals can self-assemble into one-, two- and three-dimensional superstructures.

中文翻译：

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由截断的四面体量子点生成的超结构

将均匀的纳米晶体构建块组装成有序的超结构是产生具有新兴纳米功能的介观和宏观超材料的基本策略1-10。在热力学平衡时经常采用致密、面心立方或六方密堆积排列的球形纳米晶体的堆积比非球形、多面体纳米晶体的堆积得到了更广泛的研究，尽管后者具有由积木11-13的形状产生的有趣的各向异性特性。在这里，我们报告了截断的四面体量子点纳米晶体堆积成三种不同的超结构——一维手性四螺旋，二维准晶近似超晶格和三维基于簇的体心立方单超晶——通过控制组装条件。使用实空间和互易空间中的技术，我们成功地表征了从纳米晶体平移排序到单个量子点的原子取向排列的超结构。我们的堆积模型表明，纳米晶体超结构的形成主要是由四面体的各向异性斑块引起的选择性小面接触。这项研究提供了有关将非球形纳米晶体堆积成复杂超结构的信息，并可能提高自组装纳米晶体超材料在实际应用中的潜力。截断的四面体纳米晶体可以自组装成一个，