Plasmonic quantum size effects in silver nanoparticles are dominated by interfaces and local environments

Abstract

The physical properties of metals change when their dimensions are reduced to the nano-scale and new phenomena like the Localized Surface-Plasmon Resonance (LSPR) appear. This collective electronic excitation can be tuned over a large spectral range by adapting the material, size and shape. The existing literature is as rich as controversial as e.g. size-dependent spectral shifts of the LSPR in small metal nanoparticles, induced by quantum effects, are reported to the red, to the blue or entirely absent. Here we report how complementary experiments on mass-selected small silver nanoparticles embedded in silica can yield inconsistent results on the same system: while optical absorption shows no size-effect in the range between only a few atoms and ~10 nm, a clear spectral shift is observed in single-particle electron spectroscopy. Our quantitative interpretation, based on a mixed classical/quantum model, resolves the apparent contradictions, not only within our experimental data, but also in the literature. Our comprehensive model describes how the local environment is the crucial parameter controlling the manifestation or absence of size effects.

Microcapsule‐Based Visualization Smart Sensors for Damage Detection: Principles and Applications

“…Metal nanoparticles as indicators are embedded to the surface of microcapsule to form a mechanical‐induced visualized microcapsule based on the mechanism of surface plasmons . The effects of surface plasmons such as surface‐enhanced Raman scattering and surface‐enhanced fluorescence are induced by surface plasmon of metal nanoparticles . When the microcapsules are stretched, the space of nanoparticle will be changed.…”

Ultrasmall Pd‐Cu‐Pt Trimetallic Twin Icosahedrons Boost the Electrocatalytic Performance of Glycerol Oxidation at the Operating Temperature of Fuel Cells

“…The size and shape of metal nanocrystals are key parameters that make it possible to tailor their performance in many important application fields, because the size takes control of their specific surface areas, the shape masters the exposed facets, the number of edge and corner and atom arrangement of nanocrystals . Moreover, uniform, well‐defined polygonal nanocrystals can be as building blocks to construct fascinating ordered architectures that would capture collective performances differed from single building block .…”

Physicochemical Aspects of Metal Nanoparticle Preparation

“…However, dramatic change in the nanomaterial properties happens when the diameter is below 3 nm (note: some of the authors state 5 nm or even 10 nm), which corresponds to approx. 1000 silver atoms [53][54][55]. Concerning such tiny particles, the organization of valence electrons is changed, and there is a shift from a band structure typical for metals to the organization HOMO-LUMO typical for molecular mass organization.…”

“…Concerning such tiny particles, the organization of valence electrons is changed, and there is a shift from a band structure typical for metals to the organization HOMO-LUMO typical for molecular mass organization. However, a complete shift from one layout structure to the other one happens at the dimension below 1 nm when the particles contain maximally tens of atoms, and their behavior is strongly influenced by quantum effects, which is not commonly observed in the case of nanomaterials [5,46,[55][56][57]. These particles are usually named as clusters, and their abnormal optical properties (i.e., fluorescence) are nowadays in the center of the interest of the studies focused on optical properties of nanomaterials [58][59][60][61][62][63].…”