The self-assembly of nanocrystals into ordered superlattices is a powerful strategy for the production of functional nanomaterials. The assembly of well-ordered target structures, however, requires control over the building blocks’ size and shape as well as their interactions. While nanocrystals with homogeneous composition are now routinely synthesized with high precision and assembled into various ordered structures, high-quality multicomponent nanocrystals and their ordered assemblies are rarely reported. In this paper, we demonstrate the synthesis of quantum dot–gold (QD-Au) heterodimers. These heterodimers possess a uniform shape and narrow size distribution and are capped with oleylamine and dodecyltrimethylammonium bromide (DTAB). Assembly of the heterodimers results in a superlattice with long-range orientational alignment of dimers. Using synchrotron-based X-ray measurements, we characterize the complex superstructure formed from the dimers. Molecular dynamics simulations of a coarse-grained model suggest that anisotropic interactions between the quantum dot and gold components of the dimer drive superlattice formation. The high degree of orientational order demonstrated in this work is a potential route to nanomaterials with useful optoelectronic properties.

中文翻译：

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量子点-金异二聚体纳米晶体的取向顺序自组装。

将纳米晶体自组装成有序的超晶格是生产功能纳米材料的有力策略。但是，有序目标结构的组装需要控制构建块的大小和形状以及它们之间的相互作用。虽然现在常规地以高精度合成具有均一组成的纳米晶体并且将其组装成各种有序的结构，但是很少报道高质量的多组分纳米晶体及其有序的组装体。在本文中，我们演示了量子点金（QD-Au）异二聚体的合成。这些异二聚体具有均匀的形状和狭窄的尺寸分布，并被油胺和十二烷基三甲基溴化铵（DTAB）封端。异二聚体的组装导致具有二聚体的长距离定向排列的超晶格。使用基于同步加速器的X射线测量，我们表征了由二聚体形成的复杂上层建筑。粗粒度模型的分子动力学模拟表明，二聚体的量子点和金组分之间的各向异性相互作用驱动了超晶格的形成。在这项工作中证明的高度取向次序是具有有用的光电特性的纳米材料的潜在途径。