Chinese Academy of Science (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
Nat Commun. 2017 Jan 19;8:14038. doi: 10.1038/ncomms14038.
Self-assembly of individual building blocks into highly ordered structures, analogous to spontaneous growth of crystals from atoms, is a promising approach to realize the collective properties of nanocrystals. Yet the ability to reliably produce macroscopic assemblies is unavailable and key factors determining assembly quality/yield are not understood. Here we report the formation of highly ordered superlattice films, with single crystalline domains of up to half a millimetre in two dimensions and thickness of up to several microns from nanocrystals with tens of nanometres in diameter. Combining experimental and computational results for gold nanocrystals in the shapes of spheres, cubes, octahedra and rhombic dodecahedra, we investigate the entire self-assembly process from disordered suspensions to large-scale ordered superlattices induced by nanocrystal sedimentation and eventual solvent evaporation. Our findings reveal that the ultimate coherence length of superlattices strongly depends on nanocrystal shape. Factors inhibiting the formation of high-quality large-scale superlattices are explored in detail.
个体构建块自组装成高度有序的结构，类似于原子自发生长成晶体，这是实现纳米晶体集体性质的一种很有前途的方法。然而，目前还无法可靠地生产出宏观组装体，并且尚未了解决定组装质量/产率的关键因素。在这里，我们报告了高度有序的超晶格膜的形成，这些超晶格膜的二维单晶畴可达半毫米，厚度可达几微米，其纳米晶体的直径可达数十纳米。我们结合实验和计算结果，研究了金球、立方面体、八面体和二十面体等形状的金纳米晶体的整个自组装过程，从无序悬浮液到纳米晶体沉降和最终溶剂蒸发诱导的大尺度有序超晶格。我们的发现表明，超晶格的最终相干长度强烈依赖于纳米晶体的形状。我们详细探讨了抑制高质量大尺度超晶格形成的因素。
