Enhanced detection of thiophenol adsorbed on gold nanoparticles by SFG and DFG nonlinear optical spectroscopy

Abstract : Sum frequency generation (SFG) and difference frequency generation (DFG) are applied to study vibrational resonance of the thiophenol molecule adsorbed on two different gold samples. One sample is made of 17 nm gold nanoparticles (AuNPs) fixed on a silicon substrate that has been previously functionalized with a silane monolayer (aminopropyltriethoxysilane, APTES). This sample is fully characterized through visible reflection spectroscopy and AFM. The second sample is a gold monocrystal also covered with thiophenol molecules. From their comparison, an enhancement factor of 21 is deduced for the SFG signal on AuNPs with respect to the Au(111), related to the surface plasmon resonance (SPR). From a combined analysis of the SFG and DFG spectra, we demonstrate that SFG/DFG spectroscopy is able to identify the nature of the substrate where the molecules are adsorbed. This opens new perspectives for this nonlinear spectroscopy by adding to its well-known intrinsic surface specificity, the ability to selectively probe the chemical layer capping the AuNPs.
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-00439776
Contributor : Emmanuelle Lacaze <>
Submitted on : Tuesday, December 8, 2009 - 3:19:30 PM
Last modification on : Wednesday, May 15, 2019 - 3:54:56 AM

Links full text

Identifiers

Citation

Olivier Pluchery, Humbert Christophe, Valamanesh Mehrnoush, Emmanuelle Lacaze, B. Busson. Enhanced detection of thiophenol adsorbed on gold nanoparticles by SFG and DFG nonlinear optical spectroscopy. Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2009, 11, pp.7729. ⟨10.1039/b902142f⟩. ⟨hal-00439776⟩

Share

Metrics

Record views

259