Phase Transition of Octaneselenolate Self-assembled Monolayers on Au(111) Studied by Scanning Tunneling Microscopy

Choi, Jungseok; Kang, Hye Won; Ito, Eisuke; Hara, Masahiko; Noh, Jaegeun

doi:10.5012/bkcs.2011.32.8.2623

Cited by 8 publications

(22 citation statements)

References 32 publications

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“…72 We note that the microscopic structure we have observed for monolayers fabricated from alkaneselenol appears topographically dissimilar to monolayers deposited from dialkyl diselenide (a surface that has been reported to show a substantially larger number of gold substrate defects as compared to our observations for alkaneselenol films). 85 A thorough comparison of alkaneselenol versus dialkyl diselenide self-assembly characterization is warranted.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

et al. 2014

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When alkanethiolate self-assembled monolayers on Au{111} are exchanged with alkaneselenols from solution, replacement of thiolates by selenols is rapid and complete, and is well described by perimeter-dependent island growth kinetics. The monolayer structures change as selenolate coverage increases, from being epitaxial and consistent with the initial thiolate structure to being characteristic of selenolate monolayer structures. At room temperature and at positive sample bias in scanning tunneling microscopy, the selenolate–gold attachment is labile, and molecules exchange positions with neighboring thiolates. The scanning tunneling microscope probe can be used to induce these place-exchange reactions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

et al. 2014

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“…Selenols provide a useful comparison with thiols since they come from the same group in the periodic table. 83,[94][95][96] In contrast to the hexagonal lattices formed by alkanethiols, alkaneselenols form either densely packed distorted hexagonal lattices incommensurate with the underlying Au{111} substrate, or commensurate linear missing-row structures. 73 These differences in bonding likely contribute to the differences in conductance observed between alkaneselenol and alkanethiol SAMs.…”

Section: Substrate-head-group Interfacesmentioning

confidence: 99%

From the bottom up: dimensional control and characterization in molecular monolayers

et al. 2013

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Self-assembled monolayers are a unique class of nanostructured materials, with properties determined by their molecular lattice structures, as well as the interfaces with their substrates and environments. As with other nanostructured materials, defects and dimensionality play important roles in the physical, chemical, and biological properties of the monolayers. In this review, we discuss monolayer structures ranging from surfaces (two-dimensional) down to single molecules (zero-dimensional), with a focus on applications of each type of structure, and on techniques that enable characterization of monolayer physical properties down to the single-molecule scale.

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“…STM observations also revealed that dodecaneselenolate SAMs on Au(111) have very complicated surface structures with a distorted hexagonal packing structure with a moiré pattern , and a loosely packed missing-row structure . It has been demonstrated that various selenolate SAMs with different molecular backbones are quite different from the corresponding thiolate SAMs with an identical backbone. ,− These results imply that headgroup–gold substrate and headgroup–headgroup interactions markedly affect SAM characteristics such as structural order, domain formation, packing structure, and vacancy islands. In addition, we clearly demonstrated that the formation and structure of selenolate SAMs were strongly influenced by the chemical structure of the selenium headgroup (i.e., diselenide or selenocyanate).…”

Section: Resultsmentioning

confidence: 99%

“…Octaneselenolate SAMs on Au(111) derived from dioctyl diselenide (DODC) in a 1 mM ethanol solution at RT for 24 h contained only a disordered phase with a high density of vacancy islands (approximately 20–22%) . The loosely packed striped phase with a (6 × √3)rect structure for DODC SAMs was formed in a very diluted μM solution for very short immersion times of less than 30 min . STM observations also revealed that dodecaneselenolate SAMs on Au(111) have very complicated surface structures with a distorted hexagonal packing structure with a moiré pattern , and a loosely packed missing-row structure .…”

Section: Resultsmentioning

confidence: 99%

“…Their fundamental aspects such as surface structures, thermal and electrochemical stabilities, binding energies, and charge-transport behaviors were elucidated in more detail. ,− Scanning tunneling microscopy (STM) observations revealed that dodecaneselenolate SAMs on Au(111) derived from dodecyl diselenide have very unique surface characteristics containing two different domains: a densely packed and distorted hexagonal structure with a Moiré pattern and a linear missing-row structure . STM measurements also showed that the surface structure and growth behavior of selenolate SAMs on Au(111) from dialkyl diselenides or diphenyl diselenide were markedly different from those of the corresponding alkanethiol SAMs. − 1-Adamanetaneselenol (with a spherical adamantyl backbone) led to the formation of complex selenolate SAMs with randomly distributed high-conductance molecules, which are completely different from adamantanethiolate SAMs with a uniform and highly ordered structure . Several experimental and theoretical studies revealed that the binding strength of Se–Au in SAMs is stronger than that of S–Au, which results in the large differences in surface and physical properties of selenolate and thiolate SAMs on metals. ,− …”

Section: Introductionmentioning

confidence: 99%

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Formation and Surface Structures of Highly Ordered Self-Assembled Monolayers of Alkyl Selenocyanates on Au(111) via Ambient-Pressure Vapor Deposition

et al. 2020

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The formation and surface structures of self-assembled monolayers (SAMs) of octyl selenocyanate (OSC, CH3(CH2)7-SeCN) on Au(111) prepared by solution and ambient-pressure vapor deposition were investigated by X-ray photoelectron spectroscopy and scanning tunneling microscopy (STM). STM observations revealed that OSC SAMs on Au(111) formed in a 1 mM ethanol solution at room temperature (RT) for 6 h were mainly composed of a disordered phase, whereas vapor-deposited OSC SAMs at RT for 6 h contained an ordered phase with many bright molecular rows, bright aggregates, and dark molecular defects. Therefore, we concluded that vapor deposition is a more effective method for fabricating SAMs of alkyl selenocyanates on Au(111) to achieve a a high degree of structural order compared with solution deposition. When vapor deposition temperatures increased to 348 K, OSC SAMs on Au(111) after deposition for 6 h were much more uniform, containing a small number of loosely packed domains. The ordered phase can be described as a (2√5 × 6)R49° structure. Moreover, the structural quality of OSC SAMs on Au(111) formed at a higher deposition temperature of 363 K for 1 or 6 h was markedly enhanced, showing long-range ordered domains with a few structural defects. This ordered phase can be assigned to a (√3 × 2√11)R30° structure. In this study, we report the first molecular-scale features of SAMs on Au(111) formed by adsorption of alkyl selenocyanates. We also clearly demonstrated that organic selenocyanates could be used as an excellent new precursor for the fabrication of high-quality selenolate SAMs on Au(111) using a vapor deposition method at an elevated temperature.

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Phase Transition of Octaneselenolate Self-assembled Monolayers on Au(111) Studied by Scanning Tunneling Microscopy

Cited by 8 publications

References 32 publications

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

From the bottom up: dimensional control and characterization in molecular monolayers

Formation and Surface Structures of Highly Ordered Self-Assembled Monolayers of Alkyl Selenocyanates on Au(111) via Ambient-Pressure Vapor Deposition

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