Plasmon Modes and Hot Spots in Gold Nanostar–Satellite Clusters

Shiohara, Amane; Novikov, Sergey M.; Solís, Diego M.; Taboada, J. M.; Obelleiro, F.; Liz‐Marzán, Luis M.

doi:10.1021/jp509953f

Cited by 67 publications

(61 citation statements)

References 49 publications

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“…The maximum relative SERS enhancements are similar to previous results of core−satellite nanostructures. 27,50 As expected, the experimental results demonstrate that the electromagnetic field enhancement is inversely related to the interparticle gap distance, which is in good agreement with other reported results. 2,48 3.3.…”

Section: Characterization Of the Ag Core−satellitesupporting

confidence: 92%

Plasmonic Ag Core–Satellite Nanostructures with a Tunable Silica-Spaced Nanogap for Surface-Enhanced Raman Scattering

Rong¹,

Xiao²,

Wang³

et al. 2015

Langmuir

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Plasmonic Ag core-satellite nanostructures were synthesized by utilizing the ultrathin silica shell as a spacer to generate a tunable nanogap between the Ag core and satellites. To synthesize the nanoparticles, Ag nanoparticles (Ag NPs) with a diameter of ∼60 nm were synthesized as cores, on which Raman dyes were adsorbed and then tunable ultrathin silica shells from 2.0 to 6.5 nm were coated, followed by the deposition of Ag NPs as satellites onto the silica surface. The relationships between the SERS signal and the important parameters, including the satellite diameter and the nanogap distance, were studied by experimental methods and theoretical calculations. The maximum SERS intensity of the core-satellite nanoparticles was over 14.6 times stronger than that of the isolated Raman-encoded Ag/PATP@SiO2 NP. The theoretical calculations indicated that the local maximum calculated enhancement factor (EF) of the hot spots with a 2.0 nm nanogap was 9.5 × 10(5). The well-defined Ag core-satellite nanostructures have a high structural uniformity and an anomalously strong electromagnetic enhancement for highly quantitative SERS, leading to a better understanding of hot spot formation and providing new insights into the optimal design and synthesis of the hot SERS nanostructures in a controlled manner.

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Section: Characterization Of the Ag Core−satellitesupporting

confidence: 92%

Plasmonic Ag Core–Satellite Nanostructures with a Tunable Silica-Spaced Nanogap for Surface-Enhanced Raman Scattering

Rong¹,

Xiao²,

Wang³

et al. 2015

Langmuir

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“…SERS measurements of core-satellite systems both using spherical nanoparticles and mixtures of nanorods and spheres were reported [68,69]. Liz-Marzan et al proposed that a core-satellite design comprising gold nanostar cores may offer a promising direction for the development of ultrahigh enhancing SERS substrates [70]. In this study they assembled core-satellite clusters comprising a central ∼65 nm gold nanostar surrounded by 12 nm spherical gold nanoparticles at different concentrations, which allowed to study the enhancing efficiency of this system.…”

Section: Surface-enhanced Raman Scattering Of Gnsmentioning

confidence: 99%

Physical Properties of Gold Nanostars

2015

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The most relevant applications of gold nanostars are based on their physical properties. These arise primarily from resonant oscillations of the conduction electrons of the nanoparticles called localized surface plasmon resonances (LSPR). In this chapter an introduction to the physical origin of the LSPR and the way the nano-environment affect them are provided. Finally the implication of the LSPR of gold nanostar surface-enhanced Raman scattering is also discussed.Keywords Gold nanostars • Localized surface plasmon resonance • Surfaceenhanced Raman scattering GNS show a LSPR of the core and multiple LSPRs corresponding to the tips and core-tip interactions. The latter are polarization dependent and accompanied by large local electric field enhancements at the sharp ends of the tips [1]. The locally enhanced fields have been exploited to amplify Raman signals (SERS) allowing molecular detection at zeptomolar levels [2] and, very recently, have enabled the demonstration of SERS at the single-gold nanostar level [3]. As a consequence of the confined electric field enhancement at the tips, the spectral positions of the LSPRs of a nanostar are expected to depend strongly on the dielectric environment around the tips [4]. The coupling of propagating surface plasmons and localized surface plasmons leads to enhanced electromagnetic fields which can be exploited for surface-enhanced Raman scattering and fluorescence enhancement and opens wide routes for developing new sensors for in vitro and in vivo application, which are discussed in this chapter.

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“…There are various strategies for the realization of hot spots, e.g., aggregation of NPs, satellite-systems [25,26], nanostructures fabricated by electron-beam lithography (EBL), and focused ion beam (FIB) milling. However, colloids aggregation is unpredictable random process that leads to alternating Raman enhancement and decreased reproducibility.…”

Section: Introductionmentioning

confidence: 99%