Adsorption properties of decyl thiocyanate and decanethiol on platinum substrates studied by sum-frequency generation spectroscopy
Résumé
Recently, thiocyanate groups were successfully used as precursors for thiolate assemblies. Indeed, they provide a useful alternative to thiol groups for self-assembly on metallic substrates. In order to check the adsorption properties and the quality of the thiocyanate-based self-assembled monolayers (SAMs), we use sum-frequency generation spectroscopy (SFG) and apply it to characterize the ad-layers of two similar molecules: decanethiol (DT) and decyl thiocyanate (DTCN) adsorbed on platinum surfaces. By comparing the SFG signals of the methyl and methylene vibration modes, we show that DTCN SAMs are less ordered than DT ones. These effects are related to the SAMs quality which depends on the molecular packing as highlighted by scanning tunnelling microscopy and X-ray photoelectron spectroscopy.
Mots clés
"Sum-frequency generation spectroscopy"
"Scanning tunnelling microscopy"
"X-ray photoelectron spectroscopy"
"Platinum surfaces"
"Self-assembled monolayers"
"Decanethiol"
"Decyl thiocyanate"
Sum-frequency generation spectroscopy
Scanning tunnelling microscopy
X-ray photoelectron spectroscopy
Platinum surfaces
Self-assembled monolayers
Decanethiol
Decyl thiocyanate