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Surface Lattice Resonances in Self-Assembled Arrays of Monodisperse Ag Cuboctahedra
ACS Nano ( IF 15.8 ) Pub Date : 2019-07-22 00:00:00 , DOI: 10.1021/acsnano.9b03191
Mindaugas Juodėnas 1 , Tomas Tamulevičius 1, 2 , Joel Henzie 3 , Donats Erts 4 , Sigitas Tamulevičius 1, 2
Affiliation  

Plasmonic metal nanoparticles arranged in periodic arrays can generate surface lattice plasmon resonances (SLRs) with high Q-factors. These collective resonances are interesting because the associated electromagnetic field is delocalized throughout the plane of the array, enabling applications such as biosensing and nanolasing. In most cases such periodic nanostructures are created via top-down nanofabrication processes. Here we describe a capillary-force-assisted particle assembly method (CAPA) to assemble monodisperse single-crystal colloidal Ag cuboctahedra into nearly defect-free >1 cm2 hexagonal lattices. These arrays are large enough to be measured with conventional ultraviolet–visible spectroscopy, which revealed an extinction peak with a Q-factor of 30 at orthogonal illumination and up to 80 at oblique illumination angles. We explain how the experimental extinction changes with different light polarizations and angles of incidence, and compare the evolution of the peaks with computational models based on the coupled dipole approximation and the finite element method. These arrays can support high Q-factors even when exposed to air, because of the high aspect ratio of the single-crystal nanoparticles. The observation of SLRs in a self-assembled system demonstrates that a high level of long-range positional control can be achieved at the single-particle level.

中文翻译:

单分散Ag Cuboctahedra自组装阵列中的表面晶格共振。

排列成周期性阵列的等离激元金属纳米粒子可以产生具有高Q因子的表面晶格等离子体激元共振(SLR)。这些相关的共振很有趣,因为相关的电磁场在整个阵列平面上都是局部的,从而可以进行诸如生物传感和纳米激光的应用。在大多数情况下,这种周期性的纳米结构是通过自上而下的纳米制造工艺创建的。在这里,我们描述了一种毛细管力辅助颗粒组装方法(CAPA),用于将单分散单晶胶体Ag八面体组装成几乎无缺陷的> 1 cm 2六角形晶格。这些阵列足够大,可以用常规的紫外线-可见光谱法进行测量,该光谱显示出一个消光峰和一个Q因子在正交照明下为30,在倾斜照明角度下为80。我们解释了实验消光如何随不同的光偏振和入射角而变化,并使用基于偶极近似耦合和有限元方法的计算模型比较了峰的演化。由于单晶纳米颗粒的高长径比,即使暴露在空气中,这些阵列也可以支持高Q因子。在自组装系统中对SLR的观察表明,可以在单粒子水平上实现高水平的远程位置控制。
更新日期:2019-07-22
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