Molecular-Scale Characterization of the Reaction of Ozone with Decanethiol Monolayers on Au(111)

Abstract

The chemical reaction of ozone with decanethiol monolayers on Au(111) was characterized using X-ray photoelectron spectroscopy and scanning tunneling microscopy. Our results show that exposure to ozone results in oxidation of the thiol terminus. The reaction initiates at the domain boundary network of the alkanethiol monolayer and propagates into the domains. Above a threshold surface oxygen content, the monolayer converts to a two-dimensional fluid that can subsequently recrystallize to a commensurate monolayer of partially oxidized thiol. Further exposure to ozone results in conversion of the monolayer to a fluid phase and a 10% to 30% expansion of the Au lattice at the Au−thiol interface with concomitant formation of Au islands. Our results demonstrate that crystallographic defects in monolayer films can play an important role in their chemical reactions.

ToF‐SIMS investigations of the degeneration processes of self‐assembled monolayers of alkanethiols on gold

“…After exposure to ambient air for 30 h ( Fig. 2(b) 4 , MO 3 ) can also be observed after 1 h of exposure to ambient air, but at lower intensities. With further exposure to ambient air, these mass signal intensities increase further (Fig.…”

“…After 1 week (168 h) at ambient air ( Fig. 2(d)) the SO 3 , HSO 4 and MO 3 signal intensities exceed the gold-alkanethiolate cluster and substrate-related signal intensities and dominate the mass spectra. One reason for the rapid increase in signal intensity of SO 3 , HSO 4 and MO 3 might be the high secondary ion yield of oxygen-containing secondary ions in the negative SIMS mode.…”

“…For decanethiol SAMs, Poirier et al 4 show that the degeneration starts at domain boundaries and defects, propagating into the domains. Such a degeneration process leads to decreasing areas of intact SAM domains.…”

Unusual aggregates from the oxidation of alkene self-assembled monolayers: a previously unrecognized mechanism for SAM ozonolysis?

“…The wide distribution of particle sizes, shapes and number density may be due to reaction being initiated at defects and/or steps and edges in the SAM. 9 Scanning Auger microprobe analysis was used to probe the elemental composition of particles such as that in Fig. 3a from the reaction of the C3 ¼ SAM with O 3 .…”

Molecule-Dependent Quantum Yield in Photon Emission Scanning Tunneling Microscopy of Mixed Amphiphile Monolayers on Au(111)

“…The system chosen for study is a surface mixture of reduced and oxidized alkanethiols, the structure of which is known from a prior study [9]. The paper begins with a description of the photon collecting apparatus.…”