Polymer-encapsulated silver nanoparticle monomer and dimer for surface-enhanced Raman scattering

Du, Chao; Yang, Miaoxin; You, Yu‐Meng; Chen, T.; Chen, H.Y.; Shen, Zexiang

doi:10.1016/j.cplett.2009.03.086

Cited by 17 publications

(9 citation statements)

References 26 publications

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“…In the case of a symmetric dimer in an isotropic medium, the strongest evanescent field at the surface of the nanoparticles is associated with a plasmon mode with polarization parallel to the dimer axis and field localization in the gap between the two particles. The cos 2 θ dependence has been confirmed experimentally in individual examples of dimers. ,− We have found the same overall trend (Figure S1, Supporting Information): Collectively, AgNC dimers with large enhancement factors produce a signal that follows the cos 2 θ dependence, regardless of the precise details of the configuration of each AgNC dimer. Dimers with small enhancement factors deviate from the rule, as expected when plasmonic coupling between the two AgNCs is ineffective.…”

Section: Resultssupporting

confidence: 74%

Dispersion in the SERS Enhancement with Silver Nanocube Dimers

Lee¹,

Hung²,

Lang³

et al. 2010

ACS Nano

148

130

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The SERS phenomenon was studied using a large set of silver nanocube dimers programmed to self-assemble in preset locations of a patterned substrate. This SERS substrate made it possible to demonstrate the dependence of the SERS enhancement on the geometry of the silver nanocube dimers and to quantify the dispersion in the SERS enhancement obtained in an ensemble of dimers. In addition to the effects of the gap distance of the dimer and the orientation of the dimer axis relative to the laser polarization on SERS enhancement, the data reveal an interesting dependence of the site-to-site variations of the enhancement on the relative orientation of the nanocubes in the dimer. We observed the highest heterogeneity in the SERS signal intensity with face-to-face dimers and a more robust SERS enhancement with face-to-edge dimers. Numerical calculations indicate that the plasmon resonance frequencies of face-to-face dimers shift considerably with small changes in gap distance. The resonance frequency shifts make it less likely for many of the dimers to satisfy the matching condition between the photon frequencies and the plasmon resonance frequency, offering an explanation for the large site-to-site variations in SERS signal intensity. These results indicate that plasmonic nanostructure designs for SERS substrates for real-world applications should be selected not only to maximize the signal enhancement potential but also to minimize the heterogeneity of the substrate with respect to signal enhancement. The latter criterion poses new challenges to experimentalists and theorists alike.

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Section: Resultssupporting

confidence: 74%

Dispersion in the SERS Enhancement with Silver Nanocube Dimers

Lee¹,

Hung²,

Lang³

et al. 2010

ACS Nano

148

130

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“…The SERS substrate enhancement factor values reported here are significant in magnitude; additional enhancement could be obtained by using silver instead of gold if long‐term stability is not critical or by changing the underlying substrate material 48–50. The enhancement factor values are lower than those reported for individual dimers of nanoparticles, however, the SERS response of individual dimers is highly anisotropic: strong enhancement is obtained only for a parallel orientation of the dimer axis and the laser polarization 23, 51–54. Our substrates display a uniform response regardless of orientation, which is extremely convenient for real‐world applications.…”

Section: Resultsmentioning

confidence: 74%

Self‐Assembled SERS Substrates with Tunable Surface Plasmon Resonances

Lee

Briber

et al. 2011

Adv Funct Materials

154

157

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The fabrication of surface-enhanced Raman spectroscopy (SERS) substrates that are optimized for use with specifi c laser wavelength-analyte combinations is addressed. In order to achieve large signal enhancement, temporal stability, and reproducibility over large substrate areas at low cost, only self-assembly and templating processes are employed. The resulting substrates consist of arrays of gold nanospheres with controlled diameter and spacing, properties that dictate the optical response of the structure. Tunability of the extended surface plasmon resonance is observed in the range of 520-1000 nm. It is demonstrated that the enhancement factor is maximized when the surface plasmon resonance is red-shifted with respect to the SERS instrument laser line. Despite relying on self-organization, site-to-site enhancement factor variations smaller than 10% are obtained.

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“…Recently, great efforts have been devoted to SERS investigations on the nanometric geometry and laser polarization-dependent behaviors of individual metal nanostructures, such as nanoparticle monomers/dimers/chains/ lenses [7][8][9][10], nanorods/nanowires (NWs) [11,12], NWfilm sandwich structures [13], etc. [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Individual Ag Nanowire Dimer for Surface-Enhanced Raman Scattering

You

Chen

et al. 2011

Plasmonics

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We have investigated the polarization-dependent surface-enhanced Raman scattering (SERS) of an individual Ag nanowire (AgNW) dimer, which contains two parallel closely packed AgNWs with very different lengths. Similar cos 2 θ dependence of signal intensities with respect to the polarization angle θ of the incident laser was observed from the dimeric part and the parts of the body as well as the tip of the longer AgNW. The dimeric part was demonstrated to exhibit the strongest SERS effect. The results agree well with our numerical simulations of the electric field distributions using finite element method. The SERS enhancement mechanisms at different parts of the dimer were also discussed which are different in origin.

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Polymer-encapsulated silver nanoparticle monomer and dimer for surface-enhanced Raman scattering

Cited by 17 publications

References 26 publications

Dispersion in the SERS Enhancement with Silver Nanocube Dimers

Dispersion in the SERS Enhancement with Silver Nanocube Dimers

Self‐Assembled SERS Substrates with Tunable Surface Plasmon Resonances

Individual Ag Nanowire Dimer for Surface-Enhanced Raman Scattering

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