Feng Ji, Yang Fan, Wang Xiaojing, Lyu Fenglei, Li Zhiwei, Yin Yadong
Department of Chemistry, University of California, Riverside, CA, 92521, USA.
Materials Science and Engineering Program, University of California, Riverside, CA, 92521, USA.
Adv Mater. 2019 May;31(19):e1900789. doi: 10.1002/adma.201900789. Epub 2019 Mar 29.
Great opportunities emerge not only in the generation of anisotropic plasmonic nanostructures but also in controlling their orientation relative to incident light. Herein, a stepwise seeded growth method is reported for the synthesis of rod-shaped plasmon nanostructures which are vertically self-aligned with respect to the surface of colloidal substrates. Anisotropic growth of metal nanostructure is achieved by depositing metal seeds onto the surface of colloidal substrates and then selectively passivating the seed surface to induce symmetry breaking in the subsequent seed-mediated growth process. The versatility of this method is demonstrated by producing nanoparticle dimers and linear trimers of Au, Au-Ag, Au-Pd, and Au-Cu O. Further, this unique method enables the automatic vertical alignment of the resulting plasmonic nanostructures to the surface of the colloidal substrate, thereby making it possible to design magnetic/plasmonic nanocomposites that allow the dynamic tuning of the plasmon excitation by controlling their orientation using an external magnetic field. The controlled anisotropic growth of colloidal plasmonic nanostructures and their dynamic modulation of plasmon excitation further allow them to be conveniently fixed in a thin polymer film with a well-controlled orientation to display polarization-dependent patterns that may find important applications in information encryption.
巨大的机遇不仅出现在各向异性等离子体纳米结构的生成中，还出现在控制它们相对于入射光的取向方面。在此，报道了一种逐步种子生长法，用于合成相对于胶体基底表面垂直自排列的棒状等离子体纳米结构。通过将金属种子沉积到胶体基底表面，然后选择性地钝化种子表面以在随后的种子介导生长过程中诱导对称性破缺，实现了金属纳米结构的各向异性生长。通过制备金、金 - 银、金 - 钯和金 - 铜氧化物的纳米粒子二聚体和线性三聚体，证明了该方法的通用性。此外，这种独特的方法能够使所得的等离子体纳米结构自动垂直排列在胶体基底表面，从而使得设计磁/等离子体纳米复合材料成为可能，该复合材料可通过使用外部磁场控制其取向来动态调节等离子体激发。胶体等离子体纳米结构的可控各向异性生长及其对等离子体激发的动态调制，进一步使它们能够方便地以可控取向固定在薄聚合物膜中，以显示偏振相关图案，这些图案可能在信息加密中找到重要应用。
