Surface Infrared and Raman Spectroscopy

Suëtaka, Wataru

doi:10.1007/978-1-4899-0942-8

Cited by 124 publications

(90 citation statements)

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“…[11][12][13][14] Actually most of the interest has been the roughness-induced enhancement of surface electromagnetic fields. There are many types of SERS-active surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Infrared Absorption Enhancement of Octadecanethiol on Colloidal Silver Particles

et al. 2004

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Infrared absorption measurements at normal incidence of radiation have been carried out on octadecanethiol (ODT) deposited from ethanol-water mixed solutions onto colloidal silver particles (ca. 30 nm diameter) on Si(111) substrates. The infrared absorption spectra taken as functions of silver mass thickness and ODT concentration show that the intensities of the CH 2 asymmetric and symmetric stretch modes of ODT are twice enhanced in comparison to those observed in the absence of the particles. The spectra also reveal that at any ODT concentration the absorption intensities exhibit a maximum for a particular mass thickness of the particles, indicating that the enhancement is linked to the aggregation of the particles. Contribution of the surface plasmon resonance apparently does not play a major role in the present systems. Approximately the same magnitude of enhancement is obtained for silver hydrosol particles exposed to ODT from the solution followed by depositing on the substrates. Scanning electron morphological inspection has been done on the aggregates in relation to the enhancement.

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“…[11][12][13][14] Actually most of the interest has been the roughness-induced enhancement of surface electromagnetic fields. There are many types of SERS-active surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Infrared Absorption Enhancement of Octadecanethiol on Colloidal Silver Particles

et al. 2004

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confidence: 99%

Highly Raman‐Enhancing Substrates Based on Silver Nanoparticle Arrays with Tunable Sub‐10 nm Gaps

et al. 2006

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Raman spectroscopy, which is based on the inelastic scattering of photons by chemical entities, has been successfully utilized for the investigation of adsorbed molecules on surfaces, [1][2][3] although the low cross section limits its applications.Surface-enhanced Raman scattering (SERS) has drawn a lot of attention since its discovery in 1974, [4] primarily because it can greatly enhance the normally weak Raman signal and thereby facilitate the convenient identification of the vibrational signatures of molecules in chemical and biological systems. [5] Recently, the observation of single-molecule Raman scattering has further enhanced the Raman detection sensitivity limit and widened the scope of SERS for sensor applications. [6,7] Although SERS effects can be achieved simply by exploiting the electromagnetic resonance properties of roughened surfaces or nanoparticles of Au or Ag, the fabrication of reliable SERS substrates with uniformly high enhancement factors remains the focus of much research. Spraying Au or Ag colloids on a substrate leads to an extremely high SERS signal at some local 'hot-junctions'; [6][7][8] however, it is not easy to achieve a reliable, stable, and uniform SERS signal spanning a wide dynamical range using this method. Van Duyne and coworkers have used nanosphere lithography, [9] while Liu andLee exploited soft lithography, [10] in order to fabricate Ag nanoparticle arrays with high SERS activity and improved uniformity. Käll and co-workers have shown theoretically that the effective Raman cross section of a molecule placed between two metal nanoparticles can be enhanced by more than 12 orders of magnitude.[11] Such enhancement is likely to be related to the 'hot-junctions' observed in some SERS experiments. Several theoretical groups have also investigated field enhancement for SERS from metal nanoparticle arrays. [12][13][14] Specifically, García-Vidal and Pendry proposed that very localized plasmon modes, created by strong electromagnetic coupling between two adjacent metallic objects, dominate the SERS response in an array of nanostructures.[12] The interparticle-coupling-induced enhancement was attributed to the broadening of the plasmon resonance peak because the probability of the resonance covering both the excitation wavelength and the Raman peak increases with its width. They calculated the average enhancement factor over the surfaces of an array of infinitely long Ag nanorods with semicircular cross sections, and showed that significant near-field interaction occurs between adjacent nanorods when the gap between the nanorods reaches half the value of their diameter. Other groups have studied the dependence of the enhancement factor on the gap between adjacent nanoparticles on a SERS active substrate. For example, Gunnarsson et al. investigated SERS on ordered Ag nanoparticle arrays with an interparticle gap above 75 nm. [15] Lee and co-workers were able to achieve the temperature-controlled variation of interparticle gaps between Ag nanoparticles embedded in a polymer membra...

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“…Thus, another enhancement factors should be considered here. It is well known that the intensity of the Raman scattering signal for a surface adsorbed species is enhanced by 10 5 -10 6 when a grained metal thin layer is used [15]. The strong electromagnetic (EM) field associated with the surface plasmon polariton and the collective electron resonance are considered as major reasons for the surface enhanced Raman scattering (SERS).…”

Section: Resultsmentioning

confidence: 99%

Conformational Order of Octadecanethiol (ODT) Monolayer at Gold/Solution Interface: Internal Reflection Sum Frequency Generation (SFG) Study

Nihonyanagi

Fujishima

et al. 2001

Studies in Surface Science and Catalysis

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Surface Infrared and Raman Spectroscopy

Cited by 124 publications

References 0 publications

Infrared Absorption Enhancement of Octadecanethiol on Colloidal Silver Particles

Infrared Absorption Enhancement of Octadecanethiol on Colloidal Silver Particles

Highly Raman‐Enhancing Substrates Based on Silver Nanoparticle Arrays with Tunable Sub‐10 nm Gaps

Conformational Order of Octadecanethiol (ODT) Monolayer at Gold/Solution Interface: Internal Reflection Sum Frequency Generation (SFG) Study

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