Effect of Substrate on Surface-Enhanced Raman Scattering of Molecules Adsorbed on Immobilized Silver Nanoparticles

Abstract

Silver nanoparticles were assembled on polyvinylpyridine (PVP) derivatized glass slides. Charge transfer between the adsorbed 4-aminothiophenol (PATP) and the immobilized silver nanoparticles was studied by surface-enhanced Raman spectroscopy with 1064 nm excitation, and compared with that of the silver nanoparticles in the colloid. It was demonstrated that the positive charges of the PVP layer could alter the charge distribution in the immobilized nanoparticles and induce the formation of the dipole in the nanoparticles, leading to less charge transfer from the metal to the adsorbed molecules. The coadsorption of chloride ions on the surface of the immobilized silver nanoparticles resulted in the redistribution of the charges in the nanoparticles and, in turn, altered the charge transfer between the adsorbed PATP molecules and the silver nanoparticles.

A novel reagentless amperometric immunosensor based on gold nanoparticles/TMB/Nafion-modified electrode

“…The effect of the assembled gold nanoparticles on the currents of the redox reaction of the TMB molecules could be related to the charge redistribution of the TMB molecules due to the interaction between the TMB molecules and the gold nanoparticles. Similar argument has been reported in the surface-enhanced Raman scattering study of the system with silver nanoparticles assembled on the monolayer of 4-aminothiophenol (Zhou et al, 2006). Upon the immobilization of the anti-MIgG, the redox currents of the TMB molecules dramatically decrease (Fig.…”

Surface-Enhanced Raman Scattering of 4-Aminothiophenol Adsorbed on Silver Nanosheets Deposited onto Cubic Boron Nitride Films

“…3, the spectra of PATP obtained on the AgNS/AuNP/NH2-cBN/Si(001) surface are similar to those reported by Zheng et al on silver nanoparticles in colloid. 23 The spectra are dominated with the a1 vibration modes (in-plane, in-phase modes) at 1004, 1076, 1178, and 1592 cm -1 . The bands at 1144, 1389, and 1430 cm -1 are assigned to the b2 vibrational modes, and the band at 390 cm -1 belongs to one of the vibration modes of the C-S band, most likely the bending mode of the C-S band.…”

A Novel Catalyst SiO2@NiO for Reduction of 4‐NP

“…The absorption spectra were recorded on a UV-Vis spectrophotometer every 2 minutes in the range of 200 -600 nm immediately after addition of proper mixing of 1 cm 3 of aqueous 15 mM sodium borohyride to the reaction mixture. [12] RESULTS AND DISCUSSION Characterization of NiO@SiO 2 Figure 2 shows the scan electron microcopy (SEM) images of the silica spheres and silica spheres coated with NiO, the latter is unlike the original silica spheres with smooth surfaces, a uniform layer was formed on silica microspheres. Both the functionalization of the silica particles with APTMS and the activation using Pd(II) solution are critical in this electroless deposition procedure.…”