Yoo Sungjae, Go Sungeun, Son Jiwoong, Kim Jeongwon, Lee Soohyun, Haddadnezhad MohammadNavid, Hilal Hajir, Kim Jae-Myoung, Nam Jwa-Min, Park Sungho
Department of Chemistry, Sungkyunkwan University, Suwon 440-746, South Korea.
Department of Chemistry, Seoul National University, Seoul 08826, South Korea.
J Am Chem Soc. 2021 Sep 22;143(37):15113-15119. doi: 10.1021/jacs.1c05189. Epub 2021 Aug 9.
We designed complex Au nanorings with intertwined triple rings (ANITs) in a single entity to amplify the efficacy of near-field focusing. Such a complex and unprecedented morphology at the nanoscale was realized through on-demand multistepwise reactions. Triangular nanoprisms were first sculpted into circular nanorings, followed by a series of chemical etching and deposition reactions eventually leading to ANITs wherein thin metal bridges hold the structure together without any linker molecules. In the multistepwise reaction, the well-faceted growth pattern of Au, which induces the growth of two distinctive flat facets in a lateral direction, is important to evolve the morphology from single to multiple nanorings. Although our synthesis proceeds through multiple steps in one batch without purification steps, it shows a remarkably high yield (>∼90%) at the final stage. The obtained high degree of homogeneity (in both shape and size) of the resulting ANITs allowed us to systematically investigate the corresponding localized surface plasmon resonance (LSPR) coupling with varying nanoring arrangements and observe their single-particle surface enhanced Raman scattering (SERS). Surprisingly, individual ANITs exhibited an enormously large enhancement factor (∼10), which confirms their superior near-field focusing relative to other reported nanoparticles.
我们设计了一种在单个实体中具有相互交织的三环结构的复杂金纳米环（ANITs），以增强近场聚焦的效果。通过按需进行的多步反应，实现了这种纳米级复杂且前所未有的形态。首先将三角形纳米棱镜雕刻成圆形纳米环，然后进行一系列化学蚀刻和沉积反应，最终形成ANITs，其中细金属桥将结构连接在一起，无需任何连接分子。在多步反应中，金的良好晶面生长模式会在横向诱导出两个独特的平坦晶面生长，这对于将形态从单个纳米环演变为多个纳米环很重要。尽管我们的合成在一批中经过多个步骤且无纯化步骤，但在最后阶段仍显示出非常高的产率（>∼90%）。所得ANITs所具有的高度均匀性（形状和尺寸方面）使我们能够系统地研究与不同纳米环排列相对应的局域表面等离子体共振（LSPR）耦合，并观察其单粒子表面增强拉曼散射（SERS）。令人惊讶的是，单个ANITs表现出极大的增强因子（∼10），这证实了它们相对于其他已报道的纳米粒子具有卓越的近场聚焦能力。
