Surface enhanced raman scattering of aromatic thiols adsorbed on nanostructured gold surfaces

Abstract

Abstract:In this paper we describe the use of a simple and versatile technique of templated electrodeposition through polystyrene sphere templates to produce nanostructured films of gold with regular submicron spherical holes arranged in a hexagonal close-packed structure. The templates were produced by self assembly of a monodispersed suspension of polystyrene spheres on gold substrates using capillary forces. The self assembly process was modified through the chemical modification of the gold substrate with cysteamine thiol. Films of gold were prepared by electrochemical deposition through the template. The electrochemical deposition charge and the current time curve were used to control the film height with a precision of approximately 10 nm. The colour of the nanostructured films changed as the film thickness was changed. Surface enhanced Raman Scattering spectra were recorded and used to identify very low concentrations of aromatic thiol molecules, 4-Nitrobenzenethiol (4-NBT) and 4-Aminobenzenethiol (4-ABT), adsorbed on the surface of the nanostructured gold substrates.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

The Role of Structural Flexibility in Plasmon-Driven Coupling Reactions: Kinetic Limitations in the Dimerization of Nitro-Benzenes

“…A shift in wavenumbers between experiment and simulation is likely caused by interaction of the molecules with the particle surface. In accordance with literature 35 For both reactions, the simulated Raman scattering cross-sections of the dimer form are much higher than those of the monomer form (compare Figures 3a,b to 3e,f). Indeed, the cross-section of the highest C-N stretching vibration of DMAB (DMMA) is about a factor of about 20 higher than the NO 2stretching vibration of the isolated 4NTP (4NBM).…”

The Role of Structural Flexibility in Plasmon‐Driven Coupling Reactions: Kinetic Limitations in the Dimerization of Nitro‐Benzenes

“…A shift in wavenumbers between experiment and simulation is likely caused by interaction of the molecules with the particle surface. In accordance with literature, [40] our DFT calculation of DMAB assigns the experimental peaks at 1137, 1383, and 1434 cm −1 to modes of combined CH scissoring, CN symmetric stretching, and NN stretching vibrations, respectively (Figure 3e). Similarly, we assign the high energy resonances in the 4NBM spectrum (region II) to the DMMA-modes dominated by NN stretching and the lowenergy resonances (region I) to the modes dominated by the CH scissoring and CN stretching (Figure 3f).…”

Gold Nanorod Arrays: Excitation of Transverse Plasmon Modes and Surface-Enhanced Raman Applications

“…Some papers have presented bulk spectra with peaks at 1140 cm -1 δ(CH), 1390 cm -1 ν(CC) + δ(CH), and 1430 cm -1 ν(CC) + δ(CH) though these were absent in our spectra. 31,[48][49][50] The appearance of these peaks has been attributed to the dimerization of 4ATP to form bis(4aminophenyl) disulfide, a process that is accelerated at elevated temperature and on the surface of gold. 51 The 400 mW 1064 nm laser used by Mainu et al is an order of magnitude more powerful than the laser sources used by other researchers and may explain the presence of these peaks in their bulk spectra of 4ATP.…”