Au Nanodisk-Core Multishell Nanoparticles: Synthetic Method for Controlling Number of Shells and Intershell Distance

Abstract

Au nanodisk-core multishell nanoparticles (NDCMS-NPs) were synthesized using a Au nanodisk core as a seed to deposit a controlled number of surrounding Ag layers, followed by galvanic replacement reactions with Au ions in water. Uniform Au NDCMS-NPs with controllable shell numbers and intershell distances exhibited unique surface plasmon mode shifts, which were found to be dependent on the thickness of the Ag layer. The number of shells was tuned by controlling the multistep reactions from one to five. The Au core played a critical role in terms of holding the multishell structure during the experimental procedures. We systematically followed their shape evolution by monitoring the surface plasmon resonance bands, as well as by viewing these physical changes with electron microscopy.

Nanooptics of Plasmonic Nanomatryoshkas: Shrinking the Size of a Core–Shell Junction to Subnanometer

“…30−35 For a NM with core−shell separations below 0.4 nm, calculations from time-dependent density functional theory (TDDFT) have predicted pronounced tunneling across the nanogap, which significantly modifies the absorption cross-section and the local electric field enhancements. 22 More importantly, advances in the synthesis of NMs with precise and uniform subnanometer gaps provide a better platform for experimental investigation of quantum plasmonic effects, 17,25,36,37 compared to typical nanoparticle dimer structures fabricated by various state-of-the-art techniques including high-resolution electron-beam lithography, 30 electron-beam induced manipulation, 26 dual AFM tip approaching, 28 and dropcasting. 27,31 In this Letter, we present a comprehensive investigation of the optical properties of NMs with different nanogap widths ranging from 100 nm down to the subnanometer regime.…”

Next-generation thermo-plasmonic technologies and plasmonic nanoparticles in optoelectronics

“…[reprinted with permission from ref [95,96] (C, D) Schematic representation of Au nanomatrioska synthesis and representative transmission electron microscope image (scale bar 50 nm) [reprinted with permission from[93] (E, F) Schematic representation of Au multishell synthesis and representative transmission electron microscope image. Reprinted with permission from ref [94]. …”

Tunable Multipolar Fano Resonances and Electric Field Enhancements in Au Ring-Disk Plasmonic Nanostructures

“…The polarization direction of the plane wave was parallel to the y-axis. For a single disk, the extinction spectrum (the black curve) only had a single dipole resonance peak around 565 nm with a strong intensity [ 38 ]. For a single ring, the extinction spectrum (the red curve) shows the transverse dipole bonding mode around 867 nm, which came from the symmetric coupling between the internal and external surfaces of the Au ring dipolar modes [ 25 , 39 ].…”