Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong 518055, China.
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853, United States.
Nano Lett. 2020 Oct 14;20(10):7367-7374. doi: 10.1021/acs.nanolett.0c02779. Epub 2020 Sep 9.
Constructing three-dimensional (3D) metamaterials from functional nanoparticles endows them with emerging collective properties tailored by the packing geometries. Herein, we report 3D supercrystals self-assembled from upconversion nanorods (NaYF:Yb,Er NRs), which exhibit both translational ordering of NRs and orientational ordering between constituent NRs in the superlattice (SL). The construction of 3D reciprocal space mappings (RSMs) based on synchrotron-based X-ray scattering measurements was developed to uncover the complex structure of such an assembly. That is, the two main orthogonal sets of hexagonal close-packing ()-like SLs share the [110] axis, and NRs within the SL possess orientational relationships of [120]//[100], [210]//[010], and [001]//[001]. Notably, these supercrystals containing well-aligned NRs exhibit collectively anisotropic upconversion fluorescence in two perpendicular directions. This study not only demonstrates novel crystalline superstructures and functionality of NR-based 3D assemblies but also offers a unique tool for deciphering a wide range of complex nanoparticle supercrystals.
从功能纳米粒子构建三维（3D）超材料赋予它们新兴的集体特性，这些特性可以通过包装几何形状进行定制。在此，我们报告了由上转换纳米棒（NaYF:Yb,Er NRs）自组装而成的 3D 超晶体，它在超晶格（SL）中表现出 NR 的平移有序性和组成 NR 之间的取向有序性。基于同步加速器 X 射线散射测量的 3D 倒易空间映射（RSM）的构建被开发出来，以揭示这种组装的复杂结构。也就是说，两个主要的六方密堆积（）型 SL 的正交集共享[110]轴，并且 SL 内的 NR 具有[120]//[100]、[210]//[010]和[001]//[001]的取向关系。值得注意的是，这些含有排列良好的 NR 的超晶体在两个垂直方向上表现出集体各向异性的上转换荧光。这项研究不仅展示了基于 NR 的 3D 组装体的新型晶体超结构和功能，还为解析广泛的复杂纳米粒子超晶体提供了一种独特的工具。
