Thermal and Chemical Stability of n-Hexadecanethiol Monolayers on Au(111) in O2 Environments

COMETTO, FERNANDO; RUANO, G; F. A. SORIA; A. CALDERON; P. PAREDES OLIVERA; G. ZAMPIERI; E. M. PATRITO

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 215 p. 313 - 313

0013-4686

nderstanding the mechanisms of degradation of self-assembled monolayers (SAM) is required for their use in molecular devices and in general in long term applications. In this context, we investigated the thermal and chemical stability of n-hexadecanethiolate (C16T) monolayers on Au(111) exposed to O2. The degradation of the monolayers was followed by electrochemical (EC) techniques, surface enhancement Raman spectroscopy (SERS) and high resolution photoemission spectra (HR-XPS). The C16T monolayers were heated both under N2 and O2 flux up to 480 K for different times. The degradation of the SAM in the presence of O2 is characterized by the appearance of oxidized sulfur species and sulfur atoms on the surface. The formation time in the dipping solution also affects the thermal stability of the monolayer. Molecular dynamics (MD) simulations and density functional theory (DFT) calculations were performed to elucidate the possible degradation mechanisms. MD shows that O2 molecules easily