Au Nanorings with Intertwined Triple Rings

Abstract

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 9 ), which confirms their superior near-field focusing relative to other reported nanoparticles.

Plasmonic All-Frame-Faceted Octahedral Nanoframes with Eight Engraved Y-Shaped Hot Zones

“…The snapshots of six HAADF-TEM images at 0°, ∼17°, ∼35°, ∼56°, ∼73°, and 90°r evealed that the as-synthesized Pt frame-faceted NFs retained the structural integrity with interconnected eight tripod the rims comprise plasmonically active metals such as Au, Ag, and Cu. 37 Herein, the inter-nanogaps indicate nanogaps among eight tripods (i.e., edges and vertexes regions in an octahedral fashion), and the intra-nanogaps imply narrow inner Y-shaped hot zones placed on the octahedral faces. To endow the plasmonic focusing capability, we deposited an AuAg alloy on the Pt tripod NFs by co-reduction of Ag + and Au 3+ ions, leading to plasmonic tripod frame-faceted octahedral NFs.…”

“…Because multiple-tripod NFs are patterned on each face, the narrow multiple inter- and intra-nanogaps with inner voids would collect the electromagnetic near-field in a single entity if the rims comprise plasmonically active metals such as Au, Ag, and Cu . Herein, the inter-nanogaps indicate nanogaps among eight tripods ( i.e.…”

Multiple Stepwise Synthetic Pathways toward Complex Plasmonic 2D and 3D Nanoframes for Generation of Electromagnetic Hot Zones in a Single Entity

“…By applying selective Pt growth followed by inner Au etching, triple Pt NRs connected via thin metal ligaments are successfully formed (Figure 5d,e). 39 This concept can be further extended to the synthesis of tetra-nanorings by repeating the well-faceted growth step as shown in Figure 5d (bottom panel). These structures clearly represent four intertwined NRs linked with metal bridges, demonstrating the finely tuned controllability of the sequence of steps.…”

Turing Structured Au/Graphene Oxide‐Polyethylene Glycol Thin Film for Surface Enhanced Raman Scattering Detection of Trace Dye

“…Surface‐enhanced Raman scattering (SERS), a powerful spectroscopic method, has recently emerged due to the advancement of plasmon nanoparticles and nanotechnology. [ 3–6 ] SERS offers the advantages of being extremely sensitive, nondestructive, fast sample and testing, nonlabeling, and highly portable. [ 7 ] In addition, an SERS instrument can detect various forms of analytes, including gases, liquids, and solids.…”