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Investigation of tunable surface plasmon resonances on spheroid core–shell alloy nanoparticles using DDA method

YUSHAN CHEN1, JING LIU1,* , QIUBO YE1, WEI CHEN1, CHAOYANG CHEN1

Affiliation

  1. School of Information Engineering, Jimei University, Xiamen, Fujian 361021, PR China

Abstract

In this work, numerical simulations for the absorption and scattering efficiencies of spheroid core–shell nanoparticles (CSNPs) were conducted and studied using the discrete-dipole approximation method. The characteristics of surface plasmon resonances (SPR) depend upon shell thickness, the compositions of the core and shell materials, and the aspect ratio of the constructed CSNPs. We used different core@shell compositions, specifically Au@SiO2, Ag@SiO2, Au@TiO2, Ag@TiO2, Au@Ag, and Ag@Au, for extinction spectra analysis. We also investigated coupled resonance mode wavelengths by adjusting the composition’s layer thickness and aspect ratio. In this study, we show that the extinction efficiency of the Ag@TiO2 core–shell nanoparticles (CSNPs) was higher than that of the others, and we examined the impact of TiO2 shell thickness and Ag core radius on SPR peak positions. From the extinction spectra we found that the Ag@TiO2 nanoparticle had better refractive index sensitivity and figure of merit when the aspect ratio was set to 0.3. All of the experimental results proved that the tunability of these plasmonic resonances was highly dependent on the material used, the layer thickness, and the aspect ratio of the core@shell CSNPs..

Keywords

Surface plasmon resonance, Core–shell nanoparticles, Discrete-dipole approximation, Aspect ratio.

Citation

YUSHAN CHEN, JING LIU, QIUBO YE, WEI CHEN, CHAOYANG CHEN, Investigation of tunable surface plasmon resonances on spheroid core–shell alloy nanoparticles using DDA method, Optoelectronics and Advanced Materials - Rapid Communications, 13, 3-4, March-April 2019, pp.188-194 (2019).

Submitted at: Sept. 7, 2018

Accepted at: April 8, 2019