Tunable Surface-Enhanced Raman Scattering from Large Gold Nanoparticle Arrays

Wei, Alexander; Kim, Beomseok; Sadtler, Bryce; Tripp, Steven L.

doi:10.1002/1439-7641(20011217)2:12<743::aid-cphc743>3.0.co;2-1

Cited by 171 publications

(173 citation statements)

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“…Values for G h ′ were obtained as means of distributions about a given value of γ using a 30% coefficient of variance to account for the limited precision of measurement. 5 These enhancements are in fact very similar to G h ′ values derived for crystalline 2D arrays with precisely defined spacings, particularly as γ becomes large (see Figure 7). The comparison of G h ′ with empirical G SERS values reveals similar trends with respect to γ, demonstrating good correlation between experiment and theory.…”

Section: ∇‚[σ(R)(-∇supporting

confidence: 81%

“…5 The empirical Raman signal enhancements (G SERS ) are amplified by local EM field factors and are proportional to G h with the modification that G SERS ) |E(λ)/E 0 (λ)| 2 |E(λ′)/E 0 (λ′)| 2 , where λ and λ′ are the incident and Stokes-shifted wavelengths, respectively. 2,28 In our theoretical considerations we take into account the skin effect by renormalizing the dielectric permittivity (see Supporting Information for more details).…”

Section: ∇‚[σ(R)(-∇mentioning

confidence: 99%

“…We also take into account the loss of incident field due to reflection and absorption at the air-metal interface by introducing a first-order correction to the enhancement factor G h ′ ) T 2 G av , where T is the transmission coefficient (T∼0.25 based on experimental extinction measurements). 5 Even so, the comparison between experiment and theory remains semiquantitative, as the empirical G SERS values also depend on several other factors such as chemical "first-layer" effects and the efficiency of the collection optics. Analytical EM enhancement values were calculated for 2D arrays of Au nanospheres at fixed incident wavelengths (λ ex ) 647, 785 nm), in which local order was assumed.…”

Section: ∇‚[σ(R)(-∇mentioning

confidence: 99%

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Resonant Field Enhancements from Metal Nanoparticle Arrays

et al. 2003

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Theoretical and semiempirical studies of two-dimensional (2D) metal nanoparticle arrays under periodic boundary conditions yield quantitative estimates of their electromagnetic (EM) field factors, revealing a critical relationship between particle size and interparticle spacing. A new theory based on the RLC circuit analogy has been developed to produce analytical values for EM field enhancements within the arrays. Numerical and analytical calculations suggest that the average EM enhancements for Raman scattering (G h) can approach 2 × 10 11 for Ag nanodisks (5 × 10 10 for Au) and 2 × 10 9 for Ag nanosphere arrays (5 × 10 8 for Au). Radiative losses related to retardation or damping effects are less critical to the EM field enhancements from periodic arrays compared to that from other nanostructured metal substrates. These findings suggest a straightforward approach for engineering nanostructured arrays with direct application toward surface-enhanced Raman scattering (SERS).Nanostructured metal-dielectric interfaces often exhibit enhanced optical phenomena at visible and near-infrared (NIR) frequencies via excitation of surface plasmon modes. 1,2 The enticing possibilities of engineering such properties for applications in photonics and chemical sensing have led to a resurgence of activity in the design of plasmonic materials with subwavelength dimensions. 3 Enhanced electromagnetic (EM) field effects can be generated either in a broad spectral range, as is the case for disordered metal-dielectric composites, 2,4 or at select frequencies from periodically ordered metal nanostructures. Periodicity plays a key role in tuning the optical response of the latter, and has been documented in experimental and theoretical investigations of plasmonenhanced effects such as surface-enhanced Raman scattering (SERS), 5-7 extraordinary optical transmission, [8][9][10] and robust photonic band gaps at visible and NIR wavelengths. [11][12][13] SERS has attracted widespread attention because of its demonstrated potential for single-molecule spectroscopy and chemical sensing with high information content. [14][15][16] The rational design of optimized SERS substrates remains a challenging goal, despite extensive efforts to elucidate the physical basis of signal enhancement. Several theoretical studies have described highly localized EM fields at the junction of metal nanostructures, 7,17-19 with local EM enhancement factors G loc ) |E loc (λ)/E 0 (λ)| 4 as high as 10 11 -10 12 for a two-particle system. 20 However, less attention has been paid to the average EM enhancement factors (G h ) 〈G loc 〉), which has greater relevance for the design and optimization of SERS-based chemical sensors. In this regard, García-Vidal and Pendry have provided electrodynamics calculations on periodic nanostructured metal films with G h values on the order of 10 6 , a level of activity commonly observed in many experimental systems. 7 Here we provide numerical calculations and a simple analytical theory for calculating EM field enhancements in...

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Section: ∇‚[σ(R)(-∇supporting

confidence: 81%

Section: ∇‚[σ(R)(-∇mentioning

confidence: 99%

Section: ∇‚[σ(R)(-∇mentioning

confidence: 99%

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Resonant Field Enhancements from Metal Nanoparticle Arrays

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“…(b) Specular reflectance from Au nanoparticle arrays at a 60u angle of incidence. 47 Substrate width is approximately 1 cm. Fig.…”

Section: Optical Properties Of Gold Nanoparticle Arraysmentioning

confidence: 99%

“…12(b)). 44,47 These variable reflectivities can be attributed to several effects: size-dependent optical absorption in the visible region for 2D arrays with periodicities below 40 nm; angular-dependent attenuation in reflectance as a function of surface roughness; 48 and size-dependent Mie scattering, which increase in significance for nanoparticles and metal surfaces with roughnesses of 40 nm or more. 8, 51 The 2D nanoparticle arrays exhibited size-dependent SERS activities, with signal intensities varying by two orders of magnitude under identical sampling conditions and surface coverages (see Fig.…”

Section: Optical Properties Of Gold Nanoparticle Arraysmentioning

confidence: 99%

Calixarene‐Encapsulated Nanoparticles: Self‐Assembly into Functional Nanomaterials

Wei

2006

ChemInform

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Calixarenes are excellent surfactants for enhancing the dispersion and self-assembly of metal nanoparticles into well-defined structures, particularly those with unit length scales in the 10-100 nm size range. Particles within these ensembles are strongly coupled, giving rise to unique collective optical or magnetic properties. The self-assembled nanostructures described in this feature article include 2D arrays of colloidal Au nanoparticles with size-dependent plasmonic responses, and sub-100 nm Co nanoparticle rings with chiral magnetic states. These nanoparticle assemblies may be further developed for applications in chemical sensing based on surfaceenhanced Raman scattering (SERS) and as binary elements for nonvolatile memory, respectively.

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SERS/SERRS, the Analytical Tool

Aroca

2006

Surface‐Enhanced Vibrational Spectroscopy

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Tunable Surface-Enhanced Raman Scattering from Large Gold Nanoparticle Arrays

Cited by 171 publications

References 14 publications

Resonant Field Enhancements from Metal Nanoparticle Arrays

Resonant Field Enhancements from Metal Nanoparticle Arrays

Calixarene‐Encapsulated Nanoparticles: Self‐Assembly into Functional Nanomaterials

SERS/SERRS, the Analytical Tool

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