A thermal and passivation study of self-assembled monolayers on thin gold films

Ang, X. F.; Li, F.Y.; Wei, Jun; Tan, Wei; Wong, Chee Cheong

doi:10.1016/j.tsf.2007.07.132

Cited by 10 publications

(7 citation statements)

References 16 publications

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“…The occurrence of a partial but not a complete desorption of TP0 molecules upon annealing at 463 K gives a clear indication of the presence of different molecular adlayer structures. The desorption temperature (463 K) for the chemisorbed TP0 molecules is fairly high, which suggests that TP0 monolayers are more stable than n -alkanethiol, − 1,4-Benzenedimethanethiol (BDMT), anthracenethiol (AnT), and benzenethiol (BT) monolayers, which have been found to desorb at below 373, 423, 450, and 427 K, respectively. The significant difference in desorption temperatures of these monolayers compared to that of TP0 monolayer points to the importance of energetics of the lateral interaction in determining the SAM stability.…”

Section: Discussionmentioning

confidence: 99%

“…The significant difference in desorption temperatures of these monolayers compared to that of TP0 monolayer points to the importance of energetics of the lateral interaction in determining the SAM stability. For biphenyl-based organothiolate , adlayers and alkanethiolate − adlayers, a phase transition into low-density “flat-lying” phases was observed upon increasing the annealing temperature and desorption of molecules took place from this state. In the case of TP0-SAMs, the opposite behavior was observed in such a way that the molecules resist to such a high temperature and adopt an optimal perpendicular configuration on gold surface with a perfect homogeneous arrangement and thereafter desorb.…”

Section: Discussionmentioning

confidence: 99%

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Unexpected Formation of Dense Phases along with Temperature-Induced, Self-Assembled Terphenylthiolate Monolayers on Au(111)

et al. 2016

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Self-assembled monolayers (SAMs) of terphenylthiol (TP0) prepared on Au(111) from ethanolic solution at room temperature and subsequently annealed at different temperatures of up to 473 K were investigated using scanning tunneling microscopy and infrared reflection absorption spectroscopy. Upon annealing, the TP0 adlayer formed a series of different structural phases with different molecular arrangements. Our results show that SAMs prepared at RT without annealing and SAMs annealed at 313 K exhibited the formation of a closely packed “α” structure where TP0 molecular axes are orientated almost upright. The formation of the α-phase was accompanied by the formation of a loosely packed phase (β-phase). During annealing from 333 to 473 K, the results revealed the formation of different structural phases, namely, γ, δ, ε, σ, and ϕ. With the exception of the ϕ-phase, the phases were found to form loosely packed structures with the molecular axes largely tilted away from surface normal but do not form “flat-lying” phases. Surprisingly, upon annealing at 453 K, the SAMs exhibited a phase transition to a higher dense network of molecular structure (ϕ-phase) with almost upright standing molecules. An additional annealing at 463 K led to a significant increase in the size of the well-ordered domains of the ϕ-phase at the expense of their density. At the same time, a partial desorption of the TP0-SAMs was noticed to take place. The formation of a densely packed phase upon annealing and subsequently desorption of TP0 molecules from this state completely contradicts the behavior of n-alkanethiol and other oligophenylthiol SAMs, in which desorption occurs from lying-flat geometry. The ϕ-phase, which was the only one remaining on the surface, did not cover more than 30% of the gold surface area. A further increase of the annealing temperature to 473 K caused a substantial increase in the number of the desorbed molecules. Therefore, a remarkable reduction in both the size and density of the ordered domains of the ϕ-phase was observed. On the other hand, the annealing temperature was found to have a significant influence on both the appearance and the shape of the gold islands. Moreover, it has been found that the gold islands, regardless of their shapes, were always covered by standing-up, densely packed, and ordered phases such as the α- and ϕ-phases.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Unexpected Formation of Dense Phases along with Temperature-Induced, Self-Assembled Terphenylthiolate Monolayers on Au(111)

et al. 2016

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“…Taking advantage of surface plasmon resonance spectroscopy (SPRS) which provides high surface sensitivity and the possibility of in-situ monitoring of chemical and physical processes at metal interfaces, a thermal desorption study of dodecanethiol on gold showed a decrease in the thickness of SAMs during heating. 4 Here, we extend that study by looking at how the thermal stability of SAMs is related to chain length. In this paper, * Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 80%

<I>In-Situ</I> Monitoring of the Thermal Desorption of Alkanethiols with Surface Plasmon Resonance Spectroscopy (SPRS)

Li¹,

Xf²,

Lee³

et al. 2010

J. Nanosci. Nanotech.

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Thermal desorption investigations on self-assembled monolayers (SAMs) had previously been carried out using techniques such as thermal desorption spectroscopy (TDS), scanning tunneling microscopy (STM) and X-ray photo-electron spectroscopy (XPS). In this paper, the thermal dissociation of alkanethiols (CnH(2n + 1)SH) at various chain lengths (n= 6, 12, 18) on sputtered gold layers was monitored in-situ using the Kretschmann surface plasmon resonance configuration on a spectroscopic ellipsometer. We found that the longest alkanethiol (C18) exhibits the greatest thermal stability, manifested by the least amount of angular shift, during heating, in the resonant spectral features. Predictions of desorption temperatures from SPRS for the longer chain thiols are in good agreement with XPS measurements.

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“…Presence of such a molecular layer can result in considerably lower surface energy. SAMs have been subject of intensive studies and many organic acids with saturated long chains or alkylsilanes are found to form SAMs [99][100][101].…”

Section: Passivationmentioning

confidence: 99%

Nanostructured metal surfaces and their passivation for superhydrophobic and anti-icing applications =

Safaee¹

2008

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A thermal and passivation study of self-assembled monolayers on thin gold films

Cited by 10 publications

References 16 publications

Unexpected Formation of Dense Phases along with Temperature-Induced, Self-Assembled Terphenylthiolate Monolayers on Au(111)

Unexpected Formation of Dense Phases along with Temperature-Induced, Self-Assembled Terphenylthiolate Monolayers on Au(111)

<I>In-Situ</I> Monitoring of the Thermal Desorption of Alkanethiols with Surface Plasmon Resonance Spectroscopy (SPRS)

Nanostructured metal surfaces and their passivation for superhydrophobic and anti-icing applications =

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