Effects of Solvent on the Structure of Octanethiol Self-Assembled Monolayers on Au(111) at a High Solution Temperature

Lee, Nam‐Suk; Kang, Hye Won; Ito, Eisuke; Hara, Masahiko; Noh, Jaegeun

doi:10.5012/bkcs.2010.31.8.2137

Cited by 14 publications

(24 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…33 Although the solution temperature during immersion may be crucial for determining the final SAM structure, 7,29,34 the solvent itself is another important factor for controlling the SAM surface structure. 35−38 The size of well-ordered domains and the number of depressions in alkanethiol-SAMs on gold may be strongly influenced by the solvent and immersion temperature.…”

Section: Introductionmentioning

confidence: 99%

Effects of Solvent on the Formation of Octanethiol Self-Assembled Monolayers on Au(111) at High Temperatures in a Closed Vessel: A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study

Mamun

Hahn

2012

J. Phys. Chem. C

View full text Add to dashboard Cite

Self-assembled monolayers of 1-octanethiol (OT-SAMs) on Au(111) substrates prepared using ethanol, N,N′-dimethylformamide (DMF), toluene, or hexane were examined using scanning tunneling microscopy (STM) and Xray photoelectron spectroscopy (XPS) to investigate the effects of the solvent on the molecular packing at high solution temperatures (90°C) and high pressures (21 psi) in a closed vessel. STM imaging revealed the formation of ordered OTSAMs with a (3 × √7)R11°overlayer structure on Au(111) surfaces in ethanol, whereas OT-SAMs prepared in DMF revealed large ordered domains with a (√3 × √3)R30°phase and a c(4 × 2) superstructure. OT-SAMs prepared in toluene produced a mixture of ordered and striped phases, while no clear ordered structures were observed for OT-SAMs prepared in hexane. The disposition of OT bound to the Au(111) surfaces depended on the solvent, which also affected whether the OT-SAMs formed ordered or disordered phases. The intensities of XPS peaks at 161 and 162.3 eV increased with domain disorder, possibly due to changes in the adsorption configurations of the OT molecules.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of Solvent on the Formation of Octanethiol Self-Assembled Monolayers on Au(111) at High Temperatures in a Closed Vessel: A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study

Mamun

Hahn

2012

J. Phys. Chem. C

View full text Add to dashboard Cite

show abstract

“…5,16,17 Contrary to AT SAMs, however, the structural quality of OTA SAMs did not improve after increasing the solution temperature to 50 o C, which suggests that solution temperature is not an important factor in the formation and structure of ATA SAMs on gold. Previous work from us and other groups has shown that the direct adsorption of…”

Section: 13mentioning

confidence: 87%

“…8,13 It has been found that high quality AT SAMs containing large well-ordered domains and low density VIs were formed at an elevated solution temperature. 5,16,17 Contrary to AT SAMs, however, the structural quality of OTA SAMs did not improve after increasing the solution temperature to 50 o C, which suggests that solution temperature is not an important factor in the formation and structure of ATA SAMs on gold. Previous work from us and other groups has shown that the direct adsorption of ATAs on gold in a pure solvent does not create any closely packed well-ordered SAMs irrespective of solution temperature.…”

mentioning

confidence: 87%

See 1 more Smart Citation

Direct Adsorption and Molecular Self-Assembly of Octylthioacetates on Au(111) in the Vapor Phase

Park¹,

Kang²,

Kim³

et al. 2011

Bulletin of the Korean Chemical Society

Self Cite

View full text Add to dashboard Cite

Self-assembled monolayers (SAMs) are a very promising construct for monomolecular thin films with various practical applications because they are very amenable to surface modification and functionalization of metal surfaces.1-6 Alkanethiol SAMs on gold surfaces have been thoroughly studied by a number of research groups, and their structural properties have been well characterized. Organic thiols are prone to easily oxidize to disulfides or other oxidized species that can affect the formation and structure of SAMs. 7,8 The presence of disulfides or oxidized compounds in thiol samples often yields poorly ordered SAMs containing a high defect density and disordered phases. An approach that minimizes undesirable thiol oxidation is the use of a protected thiol that is deprotected in situ before or during SAM formation. The protection of thiol groups can be readily accomplished by acetylation. SAMs derived from acetyl protected thiols (thioacetates) on gold have usually been formed via an in situ deprotection process of the acetyl group in strong acidic or basic solutions.9-11 Other deprotection techniques have also been developed that use organic compounds such as triethylamine, 12 tetrabutylammonium cyanide, 13 and 1,8-diazabicyclo[5.4.0]undec-7-ene, 8 and organic SAMs with a high degree of structural order have been successfully constructed in solutions containing these deprotection reagents.In contrast, there have been only limited reports of investigations into the direct adsorption of thioacetyl-protected organic molecules on gold in solution without any deprotection reagents. 8,9,[13][14][15] It has been observed that the direct adsorption of alkanethioacetates (ATAs) on gold in solution generates loosely packed and disordered SAMs compared to the corresponding alkanethiols (ATs). 8,13,15 A kinetics study showed that the adsorption rate is slower for ATAs in pure solvents than for ATs. 14 Fully covered monolayers from aromatic thioacetates were formed after a longer immersion period of several days or in a concentrated 30 mM solution.9 In general, organic thiol SAMs can be formed by both solution and vapor phase deposition, and both deposition methods yield identical SAM structures containing the hexagonal (√3 × √3)R30 o or c(4 × 2) structure at saturation coverage. 1,3,16 To the best of our knowledge, however, there have been no reports describing organic thioacetate SAMs on gold grown by vapor deposition.In this study, to understand the formation of thioacetate SAMs on gold depending on deposition method, we directly compared the surface structures of the acetyl-protected octylthioacetate (OTA, CH 3 (CH 2 ) 7 SCOCH 3 ), SAMs on Au (111) The STM images in Figure 1 clearly show considerable structural differences between OTA SAMs on Au(111) grown from solution and vapor deposition at 50 o C for 24 h. OTA SAMs grown from solution were mainly composed of disordered phases containing many vacancy islands (VIs, dark holes), as shown in Figure 1a. The surface structures of these OTA SAMs were nearly identical to ...

show abstract

“…3,6,7,10 Several different two-dimensional (2D) phases were observed depending on the surface coverage and preparation conditions. 3,5 2D SAMs were formed by a delicate balance between sulfur atom-gold substrate interaction and molecule-molecule interaction.…”

Section: -10mentioning

confidence: 99%

Surface Structures and Thermal Desorption Behaviors of Cyclopentanethiol Self-Assembled Monolayers on Au(111)

Kang¹,

Kim²,

Park³

et al. 2011

Bulletin of the Korean Chemical Society

Self Cite

View full text Add to dashboard Cite

The surface structures, adsorption conditions, and thermal desorption behaviors of cyclopentanethiol (CPT) self-assembled monolayers (SAMs) on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). STM imaging revealed that although the adsorption of CPT on Au(111) at room temperature generates disordered SAMs, CPT molecules at 50 °C formed well-ordered SAMs with a (2√3 × √5)R41 o packing structure. XPS measurements showed that CPT SAMs at room temperature were formed via chemical reactions between the sulfur atoms and gold surfaces. TDS measurements showed two dominant TD peaks for the decomposed fragments (C 5 H 9 + , m/e = 69) generated via C-S bond cleavage and the parent molecular species (C 5 H 9 SH + , m/e = 102) derived from a recombination of the chemisorbed thiolates and hydrogen atoms near 440 K. Interestingly, dimerization of sulfur atoms in n-alkanethiol SAMs usually occurs during thermal desorption and the same reaction did not happen for CPT SAMs, which may be due to the steric hindrance of cyclic rings of the CPT molecules. In this study, we demonstrated that the alicyclic ring of organic thiols strongly affected the surface structure and thermal desorption behavior of SAMs, thus providing a good method for controlling chemical and physical properties of organic thiol SAMs.

show abstract

Effects of Solvent on the Structure of Octanethiol Self-Assembled Monolayers on Au(111) at a High Solution Temperature

Cited by 14 publications

References 18 publications

Effects of Solvent on the Formation of Octanethiol Self-Assembled Monolayers on Au(111) at High Temperatures in a Closed Vessel: A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study

Effects of Solvent on the Formation of Octanethiol Self-Assembled Monolayers on Au(111) at High Temperatures in a Closed Vessel: A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study

Direct Adsorption and Molecular Self-Assembly of Octylthioacetates on Au(111) in the Vapor Phase

Surface Structures and Thermal Desorption Behaviors of Cyclopentanethiol Self-Assembled Monolayers on Au(111)

Contact Info

Product

Resources

About