Universal analytical modeling of plasmonic nanoparticles

Abstract

Control over the optical response of metal nanoparticles and their associated plasmons is currently enabling many promising applications in areas as diverse as biosensing and photocatalysis. In this context, experiments based upon colloid synthesis and nanofabricated structures are assisted by numerical electromagnetic modeling, which supplies predictive simulations, but not the kind of physical intuition needed for exploration of new ideas, such as one finds when simple mathematical expressions can describe a problem. This tutorial review presents and extends a simple analytical simulation method that allows us to accurately describe the optical response of metal nanoparticles, including retardation effects, without the requirement of large computational resources. More precisely, plasmonic extinction spectra and near-field enhancement are described through a small set of real numbers for each nanoparticle shape, which we tabulate for a wide selection of common morphologies. Remarkably, these numbers are independent of size, composition and environment. We further present a compilation of nanoplasmonic experimental data that are excellently described by the simple mathematical expressions here introduced.

Deciphering the Surface Composition and the Internal Structure of Alloyed Silver–Gold Nanoparticles

“…Silver is used in biomedicine owing to its antibacterial effect, and gold is applied because of its easy surface functionalization for drug delivery or tumor thermotherapy . The presence of both metals combines the advantages of each metal and leads to new properties, for example, a tunable shift in surface plasmon resonance or an enhanced SERS effect ,,…”

Lock‐In Thermography to Analyze Plasmonic Nanoparticle Dispersions

“…Therefore, the heat generation is especially strong when the wavelength of the light source is close to the wavelength for which the absorption cross‐section of the NP is maximum . Figure S1 in the Supporting Information shows the theoretical extinction, scattering, and absorption cross‐sections from 300 to 800 nm for the investigated NPs . Table S1 in the Supporting Information summarizes the theoretical values and shows the absorption efficiency values, defined as the ratio between the absorption and extinction cross‐sections, at the irradiation wavelengths.…”

Multimodal Magnetic-Plasmonic Nanoparticles for Biomedical Applications

“…and combination of magnetic and fluorescent or plasmonic properties, these nanocomposites open up the unique possibility of controlled target-directed applications. For example, plasmonic nanoparticles have unique properties involving surface plasmon resonance phenomena and enabling to achieve the intensive selective absorption or scattering of light that is widely used in sensing, bioassays, diagnostic tools, photothermal and photodynamic therapy and other biomedical applications [1][2][3][4][5][6][7][8][9].…”