Tailoring Plasmonics of Au@Ag Nanoparticles by Silica Encapsulation

Fuente: arXiv
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Main Authors: Schultz, Johannes, Kirner, Felizitas, Potapov, Pavel, Büchner, Bernd, Lubk, Axel, Sturm, Elena
Format: Preprint
Published: 2021
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author Schultz, Johannes
Kirner, Felizitas
Potapov, Pavel
Büchner, Bernd
Lubk, Axel
Sturm, Elena
author_facet Schultz, Johannes
Kirner, Felizitas
Potapov, Pavel
Büchner, Bernd
Lubk, Axel
Sturm, Elena
contents Hybrid metallic nanoparticles encapsulated in oxide shells are currently intensely studied for plasmonic applications in sensing, medicine, catalysis, and photovoltaics. Here, we introduce a method for the synthesis of Au@Ag@SiO$_2$ cubes with a uniform silica shell of variable and adjustable thickness in the nanometer range; and we demonstrate their excellent, highly reproducible, and tunable optical response. Varying the silica shell thickness, we could tune the excitation energies of the single nanoparticle plasmon modes in a broad spectral range between 2.55 and 3.25\,eV. Most importantly, we reveal a strong coherent coupling of the surface plasmons at the silver-silica interface with the whispering gallery resonance at the silica-vacuum interface leading to a significant field enhancement at the encapsulated nanoparticle surface in the range of 100\,\% at shell thicknesses $t\,$$\simeq\,$20\,nm. Consequently, the synthesis method and the field enhancement open pathways to a widespread use of silver nanoparticles in plasmonic applications including photonic crystals and may be transferred to other non-precious metals.
format Preprint
id arxiv_https___arxiv_org_abs_2105_13946
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Tailoring Plasmonics of Au@Ag Nanoparticles by Silica Encapsulation
Schultz, Johannes
Kirner, Felizitas
Potapov, Pavel
Büchner, Bernd
Lubk, Axel
Sturm, Elena
Optics
Materials Science
Hybrid metallic nanoparticles encapsulated in oxide shells are currently intensely studied for plasmonic applications in sensing, medicine, catalysis, and photovoltaics. Here, we introduce a method for the synthesis of Au@Ag@SiO$_2$ cubes with a uniform silica shell of variable and adjustable thickness in the nanometer range; and we demonstrate their excellent, highly reproducible, and tunable optical response. Varying the silica shell thickness, we could tune the excitation energies of the single nanoparticle plasmon modes in a broad spectral range between 2.55 and 3.25\,eV. Most importantly, we reveal a strong coherent coupling of the surface plasmons at the silver-silica interface with the whispering gallery resonance at the silica-vacuum interface leading to a significant field enhancement at the encapsulated nanoparticle surface in the range of 100\,\% at shell thicknesses $t\,$$\simeq\,$20\,nm. Consequently, the synthesis method and the field enhancement open pathways to a widespread use of silver nanoparticles in plasmonic applications including photonic crystals and may be transferred to other non-precious metals.
title Tailoring Plasmonics of Au@Ag Nanoparticles by Silica Encapsulation
topic Optics
Materials Science
url https://arxiv.org/abs/2105.13946