Surface-enhanced Raman scattering by citrate on colloidal silver

Siiman, Olavi; Bumm, Lloyd A.; Callaghan, R.; Blatchford, C.G.; Kerker, Milton

doi:10.1021/j100229a020

Cited by 201 publications

(132 citation statements)

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“…Citrate ions are widely utilized in the wet chemical synthesis of silver [3][4][5][6][7][8][9][10][11][12][13][14], gold [15][16][17][18][19][20][21], platinum [22] and other nanoparticles, acting as reducing (direct reduction of aqueous Ag + ions by citrate occurs under boiling or hydrothermal conditions [9][10][11][12][13]), complexing, and stabilizing agent, although the precise mechanisms are far from being fully understood. Сitrate is a key reagent for the preparation of silver nanoplates, cubes, disks, etc., as the selective adsorption of citrate on Ag (111) facets impedes their growth and promotes the yield of anisotropic particles [12,[23][24][25].…”

Section: Introductionmentioning

confidence: 99%

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

Mikhlin

Vorobyev

Сайкова

et al. 2018

Applied Surface Science

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Citrate is an important stabilizing, reducing, and complexing reagent in the wet chemical synthesis of nanoparticles of silver and other metals, however, the exact nature of adsorbates, and its mechanism of action are still uncertain. Here, we applied X-ray photoelectron spectroscopy, soft X-ray absorption near-edge spectroscopy, and other techniques in order to determine the surface composition and to specify the citrate-related species at Ag nanoparticles 3 immobilized from the dense hydrosol prepared using room-temperature reduction of aqueous Ag + ions with ferrous ions and citrate as stabilizer (Carey Lea method). It was found that, contrary to the common view, the species adsorbed on the Ag nanoparticles are, in large part, products of citrate decomposition comprising an alcohol group and one or two carboxylate bound to the surface Ag, and minor unbound carboxylate group; these may also be mixtures of citrate with lower molecular weight anions. No ketone groups were specified, and very minor surface Ag(I) and Fe (mainly, ferric oxyhydroxides) species were detected. Moreover, the adsorbates were different at AgNPs having various size and shape. The relation between the capping and the particle growth, colloidal stability of the high-concentration sol and properties of AgNPs is briefly considered.

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Section: Introductionmentioning

confidence: 99%

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

Mikhlin

Vorobyev

Сайкова

et al. 2018

Applied Surface Science

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“…Critically, the reproducibility between Ag electrodes is poor; typically exhibiting a percentage relative standard deviation (%RSD) of 40% 8 . Probably the most popular substrates for SERS are Ag colloids 6,[8][9][10][11] . However, for optimal signals often an elaborate and precise procedure is required and whereas %RSD's of 6.6% and less have been reported 6 , typically, the average citrate Ag colloid exhibits a batch-to-batch %RSD of ca.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Novel Ag on TiO₂ Films for Surface-Enhanced Raman Scattering

et al. 2004

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Novel Ag on TiO 2 films are generated by semiconductor photocatalysis and characterised by UV/Vis spectroscopy, SEM, AFM as well as assessed for SERS activity. The nature and thickness of the photodeposited Ag, and thus the degree of SERS activity, is controlled by the time of exposure of the TiO 2 film to UV light. All such films exhibit the optical characteristic (λmax ≅ 390 nm) of small (<20nm) Ag particles, although this feature becomes less prominent the thicker the film. The films comprise quite large (>40nm) Ag islands that grow and merge with increasing levels of Ag photodeposition.Tested with a benzotriazole dye probe, the films are SERS active; exhibiting a similar activity as that of 6nm thick vapour-deposited films. The Ag/TiO 2 films exhibit a lower residual standard deviation (ca. 25%) compared with Ag vapour-deposited films (ca. 45%), which is, however, still unacceptable for quantitative work. The sample-to-sample variance could be reduced significantly (<7%) by spinning the film during the SERS measurement. The Ag/TiO 2 films are mechanically robust and resistant to removal and damage by scratching, unlike the Ag vapour-deposited films. The Ag/TiO 2 films also exhibit no obvious loss of SERS activity when stored in the dark under otherwise ambient conditions. The possible extension of this simple, effective, method of producing Ag films for SERS, to metals other than Ag, and to semiconductors other than TiO 2 , is briefly discussed.

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“…For particles, the plasma resonance of conduction electrons gives rise to an absorption peak, which shifts towards longer wavelengths for increasing packing density. [1], infrared absorption [2,3] and photo electron emission [4][5][6][7]. The resistivity of small indium particles increases by six orders of magnitude when the particle size is reduced from 1 pm to 10 nm [8,9].…”

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confidence: 99%

Investigation of metal cluster layers by EELS

Seiler

Haas

Körtje

et al. 1991

Microsc. Microanal. Microstruct.

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Abstract. 2014 The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared homogeneous silver layers with cluster layers of small silver particles with diameters of about 50 nm deposited on thin Pioloform foils, respectively. The EELS spectra of the particles seem to be different in the low loss region from the spectra of homogeneous Ag layers. This can be attributed to the influence of the carbon foil and the packing density of the particles. Investigations of Sn particles on Pioloform foils were performed to obtain additional information. Furthermore, we studied the optical behavior of different layers of Ag by Photoacoustic Spectroscopy. For particles, the plasma resonance of conduction electrons gives rise to an absorption peak, which shifts towards longer wavelengths for increasing packing density.

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Surface-enhanced Raman scattering by citrate on colloidal silver

Cited by 201 publications

References 5 publications

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

Characterization of Novel Ag on TiO₂ Films for Surface-Enhanced Raman Scattering

Investigation of metal cluster layers by EELS

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Surface-enhanced Raman scattering by citrate on colloidal silver

Cited by 201 publications

References 5 publications

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

On the nature of citrate-derived surface species on Ag nanoparticles: Insights from X-ray photoelectron spectroscopy

Characterization of Novel Ag on TiO2 Films for Surface-Enhanced Raman Scattering

Investigation of metal cluster layers by EELS

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Characterization of Novel Ag on TiO₂ Films for Surface-Enhanced Raman Scattering