Atom Probe Study of 1-Octadecanethiol Self-Assembled Monolayers on Platinum (111) and (200) Surfaces

Abstract

Atom probe tomography measurements of self-assembled monolayers of 1-octadecanethiol on platinum tips were performed and their fragmentation behavior under the influence of different laser powers was investigated. The carbon backbone evaporates in the form of small hydrocarbon fragments consisting of one to four carbon atoms, while sulfur evaporates exclusively as single ions. The carbon molecules evaporate at very low fields of 5.9 V/nm, while S requires a considerably higher evaporation field of 23.4 V/nm. With increasing laser power, a weak, but noticeable trend toward larger fragment sizes is observed. No hydrocarbon fragments containing S are detected, indicating that a strong S–Pt bond has formed. The observed surface coverage of S fits well with literature values and is higher for (111)-oriented samples than for (200).

Nanoscale analysis of frozen honey by atom probe tomography

“…In general, the mechanism of field evaporation for organic species is more complex than for metals, leading to molecular fragments of C x H y /C x O y H z groups instead of single atoms. In our various APT experiments with soft matter and liquids and related DFT-based calculations 20 , 21 , 43 , 44 , 53 , we gathered increasing evidence that the field strength during the continuous field desorption is the decisive factor which in turn is mostly affected by the bonding strength of the matrix materials. For example, alkane chains strongly bonded by a thiol group to a metallic substrate evaporate in rather small hydrocarbons with one or two carbon atoms.…”

“…For example, alkane chains strongly bonded by a thiol group to a metallic substrate evaporate in rather small hydrocarbons with one or two carbon atoms. The size of the evaporated fragments becomes larger with increasing laser power which reduces the field strength 20 . On the other hand, strong covalent intramolecular bonds, but a weak intermolecular van-der-Waals interaction leads to evaporation at low field strength and the detection of complete molecular units.…”

“…One of the current trends in APT is to attain a deeper understanding of soft matter regarding evaporation and fragmentation behavior. Thin films of polyelectrolytes 17 and self-assembled monolayers (SAMs) 18 – 20 have already been examined for their chemical structure by APT. These measurements revealed that organic materials evaporate very differently from metals or semiconducting materials.…”

A Complementary Experimental and Theoretical Approach for Probing the Surface Functionalization of ZnO with Molecular Catalyst Linkers

“…In this regard, the use of atom‐probe tomography (APT) appears promising since it is able to provide chemical information with near atomic resolution in three dimensions. [ 50 ] APT can therefore be used to study the atomistic ordering and orientation of the SAMs and act as an effective supplement for other surface characterization techniques.…”

Tracking the Mn Diffusion in the Carbon-Supported Nanoparticles Through the Collaborative Analysis of Atom Probe and Evaporation Simulation

“…The community has recently started to expand the analysis capabilities to carbon-based materials, such as carbon fiber (Johansen et al, 2021; Johansen & Liu, 2021), carbon nanotubes (Raghuwanshi et al, 2020), diamond (Schirhagl et al, 2015), graphene (Exertier et al, 2021), and self-assembled decanethiol molecules (Gault et al, 2010; Stoffers et al, 2012; Solodenko et al, 2021) not limited to metals or intermetallic compounds. However, since elemental carbon has the highest intrinsic evaporation field compared with any metallic element, the accurate data interpretation of carbon materials, i.e., the carbon black support, is challenging; the evaporation field value of covalent-bonded carbon is calculated to be 103 V/nm, whereas most metals show theoretical evaporation fields in the range of 15–60 V/nm (Gault et al, 2012; Larson et al, 2013).…”