Pal Sudip Kumar, Chatterjee Hirak, Ghosh Sujit Kumar
Department of Chemistry, Assam University Silchar-788011 Assam India
RSC Adv. 2019 Dec 19;9(72):42145-42154. doi: 10.1039/c9ra07346a. eCollection 2019 Dec 18.
The intriguing light-matter interactions can be governed by controlling the particle size and shape, electromagnetic interactions and dielectric properties and local environment of the metal nanostructures. Amongst the different approaches that have been engendered to manipulate light at the nanoscale, the self-assembly of metallic nanostructures with controllable interparticle distances and angular orientations, which strongly impact their optical attributes, is one of the viable avenues to exploit their utility in a diverse range of niche applications. The simplest geometrical architectures that enable such modulations are dimers with changeable interparticle distances and trimers with an additional degree of angular orientation to correlate the plasmonic observables with the observed spectral characteristics. Wet chemical approaches have been adopted in this study for the synthesis of size-selective gold nanoparticles, and appropriate organic linkers have judiciously been employed to induce plasmonic interactions amongst the gold nanoparticles in close proximity to each other. The combination of experimental observations and electromagnetic simulations adopted to probe the plasmonic interactions revealed that the electrodynamic coupling effect was very sensitive to particle size, interparticle distances and angular orientations in these simple nanoassemblies. The capability to precisely manipulate the electric field at the junctions between these plasmon-coupled nanoparticles could pave the way for the application of these nanoassemblies in surface-enhanced spectroscopies and sensing applications.
有趣的光与物质相互作用可以通过控制金属纳米结构的粒径和形状、电磁相互作用、介电性质以及局部环境来实现。在已出现的用于在纳米尺度上操纵光的不同方法中，具有可控粒子间距离和角取向的金属纳米结构的自组装对其光学属性有强烈影响，这是在各种特定应用中利用其效用的可行途径之一。能够实现这种调制的最简单几何结构是具有可变粒子间距离的二聚体和具有额外角取向度的三聚体，以便将等离子体可观测量与观察到的光谱特征相关联。本研究采用湿化学方法合成尺寸选择性的金纳米颗粒，并明智地使用适当的有机连接剂来诱导彼此靠近的金纳米颗粒之间的等离子体相互作用。用于探测等离子体相互作用的实验观察和电磁模拟相结合表明，在这些简单的纳米组装体中，电动力学耦合效应对粒径、粒子间距离和角取向非常敏感。精确操纵这些等离子体耦合纳米颗粒之间结处电场的能力可为这些纳米组装体在表面增强光谱学和传感应用中的应用铺平道路。
