Improve the Effective Resonance Light Scattering of Three-Layered Plasmonic Au@Dielectric@Ag Bimetallic Nanoshells

Abstract

The strong light scattering from SPR has received an extraordinary attention due to the useful applications in photodetectors, cell and biomedical imaging. However, the applications using light scattering require a high scattering cross-section along with low absorption losses near the resonance wavelength. In this paper, effective plasmonic scattering of three-layered Au-Ag bimetallic nanoshells with a dielectric separate layer has been studied using the quasi-static approximation of classical electrodynamics. Because of the surface plasmon resonance (SPR)-induced intense light absorption, the effective scattering intensity is much weaker than that of scattering cross section. However, the effective scattering intensity could be improved by tuning the geometric dimension and local dielectric environment of the nanostructure. It has been found that the greatest effective scattering takes place when the outer Ag nanoshell has a thick thickness or the dielectric separate layer has a small dielectric constant. The effective scattering also depends on the inner Au sphere radius and outer surrounding dielectric constant. Because of the mode transformation of the SPR, the effective scattering could also be greatly improved when the inner Au sphere has a very small or large size. However, the effective scattering intensity changes non-monotonously as the surrounding dielectric constant increases. The greatest effective scattering could be obtained when the surrounding dielectric constant has an intermediate value. This tunable effective plasmonic scattering of Au@Ag three-layered nanoshells presents a potential for design and fabrication of plasmonic optical nanodevice based on resonance light scattering.

Geometrical Parameter Effect on Plasmonic Scattering of Bimetallic Three-Layered Nanoshells

“…The scattering efficiency exhibits a blue shift with the increasing thickness of the middle dielectric layer. The inset of Figure 4 a shows the scattering cross section has a blue-shift with increasing the thickness of due to plasmon hybridization [ 14 , 29 ]. The corresponding physical phenomenon implies that the thickness of the outer nanoshell reduces by increasing the middle dielectric layer radius.…”

“…The total diameter of the nanoshell is much smaller than the incident wavelength. Thus, the quasi-static theory can be used to calculate the scattering and absorption efficiency [ 29 , 30 ], and the electric potential that satisfies Laplace’s equation reads …”

“…Using quasi-static theory, Zhu et el. have found that the maximum effective scattering occurs at a thick thickness of nanoshell due to the plasmon mode transformation [ 29 ].…”

Bi2O2CO3/Bi2O3 Z-scheme photocatalyst with oxygen vacancies and Bi for enhanced visible-light photocatalytic degradation of tetracycline

“…However, excessive Bi might cause light scattering, thereby weakening the shoulder-shaped absorption intensity. 36 To further clarify the optical properties of the sample, the bandgap energy (E g ) of the material was calculated using the Tauc approach. As Environmental Science: Nano Paper shown in Fig.…”

Tuning Optical Properties of Plasmonic Aerosols through Ligand–Solvent Interactions

“…Spectroscopic characterization of aerosolized matter typically requires an optical path length of kilometers, which is achieved using cavity-enhanced spectroscopies (e.g., cavity ringdown laser absorption spectroscopy (CRLAS)) that use high-finesse optical cavities tuned to a specific resonance wavelength to detect the analyte of interest; significant realignment of the cavity is required to change the resonance condition, thereby inhibiting measurement of complete spectroscopic fingerprints as well as multiplexed detection of analytes over a large spectral range in a timely manner. − In this work, we exploit the larger scattering cross sections of plasmonic materials relative to other organic or inorganic matter allowing for their absorption spectra to be measured in an optical cavity with only a 10-m path length. − The work presented here builds on that of Geldmeier et al, who demonstrated the first effective generation and steady-state optical characterization of aerosolized gold nanorods and proved that it is possible to measure the steady-state optical responses of plasmonic materials in a gas cell with a short path length. Recent work from the same authors has also demonstrated the ability to control the orientational and positional order of aerosolized gold nanorods by applying an external electric field. , Other work has demonstrated the potential for materials optically trapped as aerosols to function as airborne single particle reactors, capable of detecting aerosolized biologics through Raman spectroscopic studies − and circular intensity differential scattering.…”