Plasmonic Materials for Surface-Enhanced Sensing and Spectroscopy

Abstract

Localized surface plasmon resonance (LSPR) excitation in silver and gold nanoparticles produces strong extinction and scattering spectra that in recent years have been used for important sensing and spectroscopy applications. This article describes the fabrication, characterization, and computational electrodynamics of plasmonic materials that take advantage of this concept.Two applications of these plasmonic materials are presented: (1) the development of an ultrasensitive nanoscale optical biosensor based on LSPR wavelength-shift spectroscopy and (2) the use of plasmon-sampled and wavelength-scanned surface-enhanced Raman excitation spectroscopy (SERES) to provide new insight into the electromagnetic-field enhancement mechanism.

Microstructural evolution of Au/TiO2 nanocomposite films: The influence of Au concentration and thermal annealing

“…Another important aspect of noble NPs, when dispersed in a dielectric matrix, is that their optical response strongly depends on their clustering tendency, namely the clusters size, shape and distribution [3,35,36], the interaction between them [7,37], but also on the host matrix dielectric function itself [11,[38][39][40][41].…”

“…Since changes in size, shape and distribution of Au clusters are fundamental parameters for tailoring of the LSPR effect [1][2][3]36], a set of films with a wide range of Au concentration was prepared. The films were deposited by direct current (DC) magnetron sputtering, and in order to promote the clustering of the Au nanoparticles, the as-deposited samples were subjected to an in-air annealing protocol.…”

“…The two most studied plasmonic metals are gold (Au) and silver (Ag) [3][4][5][6][7][8][9]. The first has the advantage of being chemically inert, whereas the second is preferable for some particular applications, since the damping of the SPs or LSPs is smaller than that of gold.…”

Light‐Driven Plasmonic Color Filters by Overlaying Photoresponsive Liquid Crystals on Gold Annular Aperture Arrays

“…As known, the plasmonic effect only happens in a localized area (generally less than 100 nm) near the dielectric/metal interface. [ 49 ] The alignment of the LC molecules inside and outside the annular aperture could play a signifi cant role in photoinduced refractive index modulation, thus affecting the transmittance of the whole device. Crawford et al have investigated the molecularanchoring properties of the nematic LCs in cylindrical cavities and found that an escaped radial with singular point defects (ERPD) alignment was preferably supported for an untreated cavity with its radius larger than 50 nm.…”

Faceting of Nanocrystals during Chemical Transformation: From Solid Silver Spheres to Hollow Gold Octahedra

“…Production of hollow Au nanocrystals with faceted geometry allows increased tunability of optical properties as the surface plasmon resonance spectra of a hollow metallic nanocrystal depends strongly not only on the shell thickness, but also on the detailed shape. 16,17 To produce Ag nanocrystals with reduced sizes and improved monodispersity, we performed the synthesis using a modification of the polyol process in an organic solvent and at high temperature. 6,18 The silver salt AgNO 3 was reduced by a long chain polyol such as 1,2-hexadecanediol using an organic solvent, o-dichlorobenzene (DCB).…”