Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA.
International Institute for Nanotechnology, Northwestern University, USA.
Angew Chem Int Ed Engl. 2021 Aug 23;60(35):19035-19040. doi: 10.1002/anie.202105796. Epub 2021 Jul 26.
It is critical to assemble nanoparticles (NPs) into superlattices with controlled symmetries and spacings on substrates for metamaterials applications, where such structural parameters dictate their properties. Here, we use DNA to assemble anisotropic NPs of three shapes-cubes, octahedra, and rhombic dodecahedra-on substrates and investigate their thermally induced reorganization into two-dimensional (2D) crystalline films. We report two new low-density 2D structures, including a honeycomb lattice based on octahedral NPs. The low-density lattices favored here are not usually seen when particles are crystallized via other bottom-up assembly techniques. Furthermore, we show that, consistent with the complementary contact model, a primary driving force for crystallization is the formation of directional, face-to-face DNA bonds between neighboring NPs and between NPs and the substrate. Our results can be used to deliberately prepare crystalline NP films with novel morphologies.
对于超材料应用来说，将纳米粒子（NPs）组装成具有受控对称性和间距的超晶格是至关重要的，因为这些结构参数决定了它们的性质。在这里，我们使用 DNA 将三种形状的各向异性纳米粒子（立方体、八面体和菱形十二面体）组装在基底上，并研究它们在热诱导下重新组装成二维（2D）晶状薄膜。我们报道了两种新的低密度 2D 结构，包括基于八面体 NPs 的蜂窝晶格。这里所青睐的低密度晶格在通过其他自下而上的组装技术结晶时通常不会出现。此外，我们表明，与互补接触模型一致，结晶的主要驱动力是相邻 NPs 之间以及 NPs 与基底之间形成定向的面对面 DNA 键。我们的结果可用于有目的地制备具有新颖形态的晶态 NP 薄膜。
