Enhanced photochemistry of 2‐aminopyridine adsorbed on silver colloid surfaces

Jeong, Dae Hong; Suh, Jin Soo; Moskovits, Martin

doi:10.1002/jrs.793

Cited by 19 publications

(14 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such bands have been earlier reported by several groups as ones which correlate with photo defragmentation of organic molecules bound to roughened silver surface 38 in vacuum, or adsorbed on Ag colloid in aqueous solution. 39 In our experiments, however, graphite peaks showed a fast growth over a time span of 5 to 10 s when the substrate was exposed to 10 mW laser radiation, but no significant increase in intensity of these bands was observed at later times. Since Figure 4.…”

Section: Sers Measurements Of R6gcontrasting

confidence: 64%

“…A strong chemisorption of heterocyclic nitrogen-containing compounds is well documented in the literature. 38,39 It is expected that two nitrogen atoms provide strong chemisorption of HEPES molecules at the silver surface, and also result in flat orientation of piperazine ring at the surface. Negatively charged sulfate groups of adsorbed HEPES molecules present strongly attractive adsorption sites for positively charged R6G molecules.…”

Section: R6g Binding From Buffer Solutionmentioning

confidence: 99%

See 1 more Smart Citation

In situ SERS study of Rhodamine 6G adsorbed on individually immobilized Ag nanoparticles

Pristinski

Tan

Erol

et al. 2006

J Raman Spectroscopy

131

View full text Add to dashboard Cite

We report a study on polymer-mediated immobilization of non-aggregated Ag nanoparticles on planar glass substrates and the resultant surface-enhanced Raman scattering (SERS) activity using Rhodamine 6G (R6G) as a model molecule. Ag colloidal solution with an average particle diameter of 70 nm was prepared by citrate reduction of AgNO 3 using the Lee-Meisel method, and subsequent fractionation by filtration. A self-assembled polyallylamine hydrochloride (PAH) monolayer was employed as the intermediate polymer layer. We have shown that the coverage density of Ag nanoparticles on the glass substrates correlates with the amount of adsorbed PAH. This parameter can be easily controlled by varying the pH and ionic strength during polymer deposition. The highest coverage density was obtained for the polymer deposition from buffer solutions at pH 9.0, which additionally contained 0.25 M NaCl. The SERS-active substrates were robust and stable in 0.5 M NaCl solutions, as well as under extreme acidic and basic conditions. The glass substrates with immobilized non-aggregated Ag nanoparticles exhibited SERS enhancement and provided in situ detection sensitivity of R6G at 5 ppt level, with estimated surface coverage of two to four R6G molecules per silver particle. We found that adsorption of R6G in the presence of N-(2-hydroxyethyl)piperazine-N -(2-ethanesulfonic acid) (HEPES) buffer resulted in complete inhibition of photodecomposition of adsorbed R6G molecules. Studies of the effect of sodium chloride on the SERS activity of the glass substrates with individually attached nanoparticles showed that chloride anions resulted in a two to threefold increase in SERS intensity. Our approach has enabled the isolation of chloride-activated SERS enhancement from contributions arising from nanoparticle aggregation. The observed SERS enhancement in salt solutions results from coadsorption of chloride ions by the silver surface, and manifests itself in changing of orientation of adsorbed R6G molecules. The observed enhancement was reversed by exposing the substrate to 514-nm laser radiation, which resulted in the cleavage of Ag-Cl bonds.

show abstract

Section: Sers Measurements Of R6gcontrasting

confidence: 64%

Section: R6g Binding From Buffer Solutionmentioning

confidence: 99%

In situ SERS study of Rhodamine 6G adsorbed on individually immobilized Ag nanoparticles

Pristinski

Tan

Erol

et al. 2006

J Raman Spectroscopy

131

View full text Add to dashboard Cite

show abstract

“…The hypothesis is that SERS intensities are proportional to the surface concentration of 8BrAd or adenine. 56,58,62,63 This suggested that the rate of PMCR could be closely associated with the incident laser energy. It is noticed in our experiment that the baseline remains constant at the same potentials.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Plasmonic Hot Electron-Mediated Hydrodehalogenation Kinetics on Nanostructured Ag Electrodes

et al. 2020

View full text Add to dashboard Cite

An attractive field of plasmon-mediated chemical reactions (PMCRs) is developing rapidly, but there is still incomplete understanding of how to control the kinetics of such a reaction related to hot carriers. Here, we chose 8-bromoadenine (8BrAd) as a probe molecule of hot electrons to investigate the influence of the electrode potential, laser wavelength, and power on the PMCR kinetics on silver nanoparticle-modified silver electrodes. Plasmonic hot electron-mediated cleavage of the C–Br bond in 8BrAd has been investigated by combining in situ electrochemical surface-enhanced Raman spectroscopy and density functional theory calculations. The experimental and theoretical results reveal that the energy position of plasmon relaxation-generated hot electrons can be modulated conveniently by applied potentials and laser light. This allows the proposal of a mechanism of modulating the matching energy of the hot electron of plasmon relaxation to promote the efficiency of PMCRs in electrochemical interfaces. Our work will be helpful to design surface plasmon resonance photoelectrochemical reactions on metal electrode surfaces of nanostructures with higher efficiency.

show abstract

“…31,47,49,50 The high intensity of this band indicates the interaction of the amino groups with the surface of the colloidal particles. 51 The broad and weak band at 1340 cm À1 is attributable to the symmetric stretching mode of the nitro groups. 33,35,49,52 The Raman spectrum of the silver colloid after acidification with HCl is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Tuning the Surface-Enhanced Raman Scattering Effect to Different Molecular Groups by Switching the Silver Colloid Solution pH

et al. 2009

View full text Add to dashboard Cite

Silver colloids were produced for surface-enhanced Raman scattering (SERS) experiments using hydroxylamine hydrochloride as the reduction agent. The roles of hydroxylamine hydrochloride and bulk solution pH values in the formation of functional groups on the surface of silver colloids and in determining the dimensions of silver colloids were examined using Raman, Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, atomic force microscopy (AFM), and zeta-size measurements. The spectrum of hydroxylamine hydrochloride reduced silver colloids was compared with the spectrum of sodium borohydride reduced colloids. The effect of colloid solution pH on SERS results was demonstrated using analyte molecules with biological significance, such as ribonucleic acid, egg albumin, L-alpha-phosphatidylcholine, and glucose. In general, it was shown that at high pH values the SERS effect was more pronounced due to the surface functional groups and colloid dimensions, and sharp, high spectral intensity values were obtained. At low pH values, protonation and rapid aggregation of colloids occurred and the surface chemistry was different. Depending on the analyte, bands were shifted, broadened, and/or the enhancement effect was reduced. Using Pseudomonas aeruginosa PAO1 and Streptococcus mutans it was also shown that by changing the solution bulk pH value, it was possible to enhance the response from different molecular groups in the bacteria and obtain different spectra from the same bacteria strain and the process was reversible. It was concluded that it is possible to produce site- or molecule-specific metal colloids and to tune the SERS effect to certain functional groups of analytes by means of the pH of colloidal suspension.

show abstract

Enhanced photochemistry of 2‐aminopyridine adsorbed on silver colloid surfaces

Cited by 19 publications

References 21 publications

In situ SERS study of Rhodamine 6G adsorbed on individually immobilized Ag nanoparticles

In situ SERS study of Rhodamine 6G adsorbed on individually immobilized Ag nanoparticles

Plasmonic Hot Electron-Mediated Hydrodehalogenation Kinetics on Nanostructured Ag Electrodes

Tuning the Surface-Enhanced Raman Scattering Effect to Different Molecular Groups by Switching the Silver Colloid Solution pH

Contact Info

Product

Resources

About