Self-assembly of subwavelength nanostructures with symmetry breaking in solution
Self-assembly of subwavelength nanostructures with symmetry breaking in solution
复制标题
溶液中对称性破缺的亚波长纳米结构自组装
DOI：
10.1039/c5nr06738c
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发表时间：
2016
期刊：
影响因子：
6.7
通讯作者：
Tian Zhong-Qun
中科院分区：
文献类型：
--
作者：
Tian Xiang-Dong;Chen Shu;Zhang Yue-Jiao;Dong Jin-Chao;Panneerselvam Rajap;iyan;Zhang Yun;Yang Zhi-Lin;Li Jian-Feng;Tian Zhong-Qun
具有对称性破缺的纳米结构可以允许暗等离子体激元模式和亮等离子体激元模式之间的耦合，以诱导强Fano共振。然而，它仍然是一个艰巨的挑战，制备自下而上的自组装亚波长不对称纳米结构，特别是低于5 nm的纳米结构之间的适当间隙在溶液中。在这里，我们提出了一种可行的自组装方法来制备由Ag纳米立方体和Au纳米球组成的纳米结构，它们具有可调的尺寸（Au纳米球为90 - 250 nm; Ag纳米立方体为100 - 160 nm），同时通过1 - 5 nm厚度的二氧化硅壳来控制纳米间隙。4-巯基苯甲酸（MBA）的拉曼标记有助于自组装过程，并赋予亚波长非对称纳米结构表面增强拉曼散射（SERS）活性。此外，厚的二氧化硅壳（厚度超过50 nm）可以原位涂覆在自组装纳米结构上，以稳定整个纳米结构，为生物应用铺平道路。对单个Ag纳米立方体和Au纳米球二聚体进行具有360 °偏振分辨率的单粒子散射光谱，与高分辨率TEM表征相关。不对称二聚体具有很强的构型和极化依赖性Fano共振性质。总的来说，本文报道的基于溶液的自组装方法为制备具有最佳性能的多种多组分纳米材料开辟了新的机会。
Nanostructures with symmetry breaking can allow the coupling between dark and bright plasmon modes to induce strong Fano resonance. However, it is still a daunting challenge to prepare bottom-up self-assembled subwavelength asymmetric nanostructures with appropriate gaps between the nanostructures especially below 5 nm in solution. Here we present a viable self-assembly method to prepare symmetry-breaking nanostructures consisting of Ag nanocubes and Au nanospheres both with tunable size (90–250 nm for Au nanospheres; 100–160 nm for Ag nanocubes) and meanwhile control the nanogaps through ultrathin silica shells of 1–5 nm thickness. The Raman tag of 4-mercaptobenzoic acid (MBA) assists the self-assembly process and endows the subwavelength asymmetric nanostructures with surface-enhanced Raman scattering (SERS) activity. Moreover, thick silica shells (above 50 nm thickness) can be coated on the self-assembled nanostructures in situ to stabilize the whole nanostructures, paving the way toward bioapplications. Single particle scattering spectroscopy with a 360° polarization resolution is performed on individual Ag nanocube and Au nanosphere dimers, correlated with high-resolution TEM characterization. The asymmetric dimers exhibit strong configuration and polarization dependence Fano resonance properties. Overall, the solution-based self-assembly method reported here is opening up new opportunities to prepare diverse multicomponent nanomaterials with optimal performance.