Plasmonic Cyclic Au Nanosphere Hexamers

Abstract

properties that are different from those of single-particle counterparts. For example, plasmonic chains [5] or oligomer-type assemblies [6][7][8] made by spatial placement of Au NSs have been explored in diverse plasmonic applications, ranging from sensing, [9] bioimaging, [10] and surfaceenhanced Raman scattering (SERS) [11][12][13][14] to non-linear optics, such as plasmonic hybridization, [15,16] and Fano resonance. [17] To realize such structures, conventional top-down lithographical approaches using e-beam lithography with high fidelity as well as high-precision has been frequently adopted, but this approach often requires delicate hands-on skills and expensive instruments. Additionally, e-beam lithography becomes extremely difficult when small gaps between NPs are desired. As an

Wet‐chemical synthesis of two‐dimensional complex nanorings for near‐field focusing

“…(c) Plasmonic cyclic Au nanosphere hexamer. Reproduced with permission from Kim et al 65 Copyright 2023 John Wiley and Sons. (d) Sphere‐in‐ring and sphere‐on‐ring structures.…”

“…To harness the inherent strong near‐field enhancement produced within intra‐nanogap, the shape transformation of individual entities into self‐assembled structures, specifically cyclic Au nanosphere hexamers, were reported (Figure 3c). 65 The synthesis of cyclic plasmonic Au nanosphere hexamers consists of six steps: (1) conversion of triangular Au nanoplates to circular Au nanoplates through etching of the vertex region of triangular Au nanoplates, 66 (2) regrowth of Au to transform the circular Au nanoplates into hexagonal Au nanoplates, 67 (3) selective deposition of Au on the vertex region of hexagonal Au nanoplates by carefully tuning the electrochemical potential to prepare tip‐blobbed hexagonal Au nanoplates, (4) site‐selective deposition of Pt along the vertex and edge regions of tip‐blobbed hexagonal Au nanoplates, (5) selective etching of inner Au templates, and (6) regrowth of Au. This unique colloidal assembly consists of six interconnected nanospheres linked by thin metal ligaments in a cyclic pattern.…”

Chiroplasmonic DNA Scaffolded “Fusilli” Structures

“…Chirality, a key feature of biomolecules, can be transferred into artificial nanomaterials either by producing crystals with chiral shapes or by arranging nonchiral nanocrystals into chiral geometries. − The encoding of structural three-dimensional (3D) information into polymers, where the final shape is dictated by the monomer sequence, showed great promise in this field. , This goal could be achieved by the use of commercially available custom-sequence synthetic DNA and its ability to self-assemble into predetermined geometries in water, following a set of simple hydrogen bond interactions, termed Watson–Crick base-pairing rules. In recent years, this approach sprouted a number of opportunities and challenges, in particular in the fields of nanotechnology and material science. ,− Specifically, due to the large extinction coefficient value associated with their localized plasmon resonance, among other materials, plasmonic nanoparticles (e.g., gold nanoparticles, AuNPs) were the object of extensive experimental efforts to produce materials with designed plasmonic properties − and patterned , or chiroplasmonic geometries. , Several applications of such hybrids were proposed, including their use for imaging mechanical functions of nanoscale machines, ,, their employment as sensors, and their potential application as waveguides …”

Customized Self-Assembled Gold Nanoparticle-DNA Origami Composite Templates for Shape-Directed Growth of Plasmonic Structures

“…The strength of LSPR of gold nanostructures is mainly affected by their size and shape, so it is crucial to realize the controllable synthesis of gold nanostructures. Traditional synthesis methods have been employed to create gold nanostructures with regular shapes, such as cubes, , rods, and triangles. , However, synthesizing more complex and diverse structures typically involves a lengthy process of etching and regeneration, which can be quite complicated. − …”