Localized surface plasmon resonance modes on an asymmetric cylindrical nanorod dimer

2016 ◽  
Vol 30 (22) ◽  
pp. 1650280 ◽  
Author(s):  
Rui-Bing Wang ◽  
Zhi-Dong Zhang ◽  
Guo-Tai Jiao ◽  
Chen-Yang Xue ◽  
Shu-Bin Yan ◽  
...  

The extinction spectra and electric field distribution of an asymmetric cylindrical nanorod dimer (ACND) are calculated by discrete dipole approximation. The ACND is composed of two linear orders of cylindrical silver nanorods with different radii and lengths. The effects of the structural parameters of ACND on the localized surface plasmon resonance (LSPR) mode are also studied. Results show two resonance peaks in the extinction spectra of ACND: the higher-energy anti-bonding mode and the lower-energy bonding mode. The interaction of two hybridization plasmonic resonance modes produces an asymmetric line shape in the extinction spectra, which is considered to be a Fano resonance profile.

NANO ◽  
2015 ◽  
Vol 10 (08) ◽  
pp. 1550117
Author(s):  
Chao Liu ◽  
Jingwei Lv ◽  
Famei Wang ◽  
Qiang Liu ◽  
Haiwei Mu ◽  
...  

Multilayered nanoshells have attracted much attention due to their unique optical, electronic and magnetic properties. In this work, numerical calculation using discrete dipole approximation (DDA) is conducted to investigate the quad-layered metal nanoshell consisting of a particle with a dielectric silica (SiO2) core, inner cadium sulfide (CdS) shell, middle indium tin oxide (ITO) shell and outer metal silver (Ag) shell. The phenomenon is interpreted by plasmon hybridization theory and the Ag–ITO–CdS–SiO2 multilayered nanoshells are studied by extinction spectra of localized surface plasmon resonance. The variation in the spectrum peak with nanoparticle thickness and refractive index of the surrounding medium is derived. The electric field enhancement contour around the nanoparticles under illumination is analyzed at the plasmon resonance wavelength. The [Formula: see text], [Formula: see text], and [Formula: see text] modes red-shift with the refractive index of the surrounding medium and increase in the layer thickness causes either blue-shift or red-shift as shown by the extinction spectra. The mechanism of the red-shift or blue-shift is discussed. The [Formula: see text] mode blue-shifts and furthermore, the [Formula: see text] and [Formula: see text] modes of the Ag coated multilayered nanostructure are noticeable by comparing the extinction efficiency spectra of the Au–ITO–CdS–SiO2 and Ag–ITO–CdS–SiO2 multilayered nanoshells.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mao Sui ◽  
Sundar Kunwar ◽  
Puran Pandey ◽  
Jihoon Lee

Abstract Multi-metallic alloy nanoparticles (NPs) can enable the advanced applications in the energy, biology, electronics, optics and catalysis due to their multi-functionality, wide tunable range and electronic heterogeneity. In this work, various mono-, bi- and tri-metallic nanostructures composed of Ag, Au and Pt are demonstrated on transparent c-plane sapphire (0001) substrates and the corresponding morphological and optical characteristics are thoroughly investigated. The resulting Pt and AuPt NPs in this study demonstrate much enhanced LSPR responses as compared to the pure Pt NPs from the previous studies, which was contributed by the synergistic effect of Au and Pt and improved surface morphology. These results are sharply distinct in terms of surface morphology and elemental variability from those obtained by the dewetting of monometallic Ag, Au and Pt films under the similar growth conditions, which is due to the distinct dewetting kinetics of the bi-layer and tri-layer films. These NPs exhibit strongly enhanced localized surface plasmon resonance (LSPR) bands in the UV-VIS wavelengths such as dipolar, quadrupolar, multipolar and higher order resonance modes depending upon the size and elemental composition of NPs. The LSPR bands are much stronger with the high Ag content and gradually attenuated with the Ag sublimation. Furthermore, the VIS region LSPR bands are readily blue shifted along with the reduction of NP size. The Ag/Pt bi-layers and Ag/Au/Pt tri-layers are systematically dewetted and transformed into various AgPt and AgAuPt nanostructures such as networked, elongated and semispherical configurations by means of enhanced surface diffusion, intermixing and energy minimization along with the temperature control. The sublimation of Ag atoms plays a significant role in the structural and elemental composition of NPs such that more isolated and semispherical Pt and AuPt NPs are evolved from the AgPt and AgAuPt NPs respectively.


NANO ◽  
2019 ◽  
Vol 14 (06) ◽  
pp. 1950071
Author(s):  
Haiwei Mu ◽  
Jianxin Wang ◽  
Qiang Liu ◽  
Wei Liu ◽  
Xianli Li ◽  
...  

The extinction spectral properties based on localized surface plasmon resonance (LSPR) of the concentric dual-ring nanodisk (CDRN) structure are investigated by discrete dipole approximation (DDA) and plasmon hybridization theory. The CDRN nanostructure shows flexible tunable multipole resonances in the near-infrared regime and the coupled resonance wavelengths depend on the structural parameters of the nanostructure, which has great potential in multichannel LSPR-based bio-sensing applications.


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4803 ◽  
Author(s):  
Hai Liu ◽  
Cong Chen ◽  
Yanzeng Zhang ◽  
Bingbing Bai ◽  
Shoufeng Tang

This paper proposes a methane sensor based on localized surface plasmon resonance (LSPR) of a hexagonal periodic gold nanoring array. The effects of structural parameters on the extinction spectrum and refractive index (RI) sensitivity are analyzed to obtain optimal parameters. In particular, the RI sensitivity can reach 550.08 nm/RIU through improvement of the sensor structure, which is an increase of 17.4% over the original value. After coating a methane-sensitive membrane on the inner and outer surfaces of the gold rings, the methane concentration can be accurately measured with a gas sensitivity of −1.02 nm/%. The proposed method is also applicable to quantitative analyses of components concentration and qualitative analyses of gas composition.


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