Plasmonic Enhancement of Local Fields in Ultrafine Metal Nanoparticles

Abstract

We present an analysis of ultrafine metallic nanoparticles (1–15 nm) with respect to electromagnetic field generation by plasmonic excitations. A number of structures with different symmetries and geometries are studied in order to analyze the distributions of plasmonically generated near-electric fields and the concentration of hot and cold spots around the particles. The study is made possible by the recent development of an extended discrete interaction model (Ex-DIM) where the explicit dependency of the plasmonic spectra on the structure and composition of particles in the range of 1–15 nm is accounted for. With the Ex-DIM, the optical response of the internal crystal structure of the nanoscale particles can be visualized, thereby making it possible to predict the dependence of the generated local fields with respect to the position of the particles relative to the external field polarization. The results indicate rather surprising concentrations of the plasmon fields in very confined hot spots also in cases when the particles retain a high symmetry. The consequence of the findings of this study when using small symmetric nanoparticles for near-field imaging is briefly discussed.

Nature of the Anomalous Size Dependence of Resonance Red Shifts in Ultrafine Plasmonic Nanoparticles

“…This fitting only needs to be performed once since this determines the interaction for a specific atom in any system. In the fitting of the element-specific parameters, the position of the surface plasmon resonance (SPR) and interband transitions as a function of size of the particle are taken directly from experiments. ,− The maximum value of the extinction cross section is fitted to the classical results . For all fitting, we assume that the experiments have been performed at room temperature, which we set to 293.15 K.…”

Influence of plasmons on the luminescence properties of solvatochromic merocyanine dyes with different solvatochromism

“…1,2 Currently, it is also possible to predict the distribution of the electric field strength around plasmon NPs based on geometry, composition, shape and the characteristics of the environment using numerical calculations within the extended discrete interaction model. [3][4][5] It is known that the LSPR effect leads to a significant enhancement of the electromagnetic field around metallic NPs, which can be employed in different applications where light-matter interaction is used. For example, the LSPR effect is used in surface-enhanced Raman spectroscopy (SERS) to achieve ultrahigh sensitivity of sensors in the detection of single molecules, which is very important in fundamental science as well as in industrial applications.…”

“…For example, the LSPR effect is used in surface-enhanced Raman spectroscopy (SERS) to achieve ultrahigh sensitivity of sensors in the detection of single molecules, which is very important in fundamental science as well as in industrial applications. [3][4][5][6][7][8][9][10] The LSPR effect of NPs is employed in studies of thermally stimulated processes, such as in photothermal cancer therapy, [11][12][13][14] photothermal imaging, 15 drug delivery, 16 photothermal melting of nanomaterials, 6,17,18 and photoacoustics. 19,20 Metallic NPs are also used for enhancing photocatalytic and photoinduced processes, since in this case activation of new reaction pathways, that are unattainable under normal conditions, is possible.…”

“…1,2 Currently, it is also possible to predict the distribution of the electric field strength around plasmon NPs based on geometry, composition, shape and the characteristics of the environment using numerical calculations within the extended discrete interaction model. 3–5…”

Interfacial-Shear-Mediated Snowball Assembly of Hotspot-Rich Silver Pompon Architectures for Tailored Surface-Enhanced Raman Scattering Responses

“…As a nondestructive, high-specificity, and single-molecule-level fingerprint characterization technique, surface-enhanced Raman scattering (SERS) is of considerable interest in various areas, including biosensing, , catalysis, , medical science, and food safety. , Plasmonic nanocrystals are often used as the test platform in the SERS application. The prominently enhanced Raman signal is known to be associated with the collective electron oscillation of the localized surface plasmon resonance (LSPR), which is highly dependent on the geometric property of plasmonic nanocrystals. Hence, metal nanocrystals (e.g., Au, Ag, and Cu) with diverse structures, sizes, and shapes have been largely prepared to create multiple photoelectric fields (i.e., hotspots) and achieve a superior signal-enhanced performance .…”