HREELS, XPS, and Electrochemical Study of Benzenethiol Adsorption on Au(111)

Whelan, Caroline M.; Smyth, and Malcolm R.; Barnes, Colin

doi:10.1021/la9806202

Cited by 133 publications

(151 citation statements)

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“…benzenethiol on Au(111). 22 However, XPS does not allow distinguishing whether the thiolates coordinate to gold surface atoms or adatoms. On Cu(111), TMB room temperature deposition resulted in bonds with surface atoms.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…In the literature this species is assigned to chemisorbed sulfur on Au(111) with a reported binding energy of 160.95 eV. 22,26,27 According to a quantitative analysis 43 % of sulfur is still in S-Au-S linkages, 48 % correspond to the unassigned species, the remaining 9 % correspond to chemisorbed sulfur.Since there is no drastic change in XPS upon annealing at 250 °C -the temperature where the ST emerged -the initial assumption was that motif 4 is chemically equivalent to motif 2 and 3, i.e. molecules are connected via S-Au-S linkages.…”

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confidence: 99%

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From Au–Thiolate Chains to Thioether Sierpiński Triangles: The Versatile Surface Chemistry of 1,3,5-Tris(4-mercaptophenyl)benzene on Au(111)

et al. 2016

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Self-assembly of 1,3,5-tris(4-mercaptophenyl)benzene (TMB) -a three-fold symmetric, thiol functionalized aromatic molecule -was studied on Au(111) with the aim to realize extended Authiolate linked molecular architectures. The focus lay on resolving thermally activated structural and chemical changes by a combination of microscopy and spectroscopy. Thereby Scanning Tunneling Microscopy provided submolecularly resolved structural information, while the chemical state of sulfur was assessed by X-ray Photoelectron Spectroscopy. Directly after room temperature deposition only less well ordered structures were observed. Mild annealing promoted the first structural transition into ordered molecular chains, partly organized in homochiral molecular braids. Further annealing led to self-similar Sierpi ski triangles, while annealing at even higher temperatures again resulted in mostly disordered structures. Both the irregular aggregates observed at room temperature and the chains were identified as metalorganic assemblies, whereby two out of the three intermolecular binding motifs are energetically equivalent according to Density Functional Theory simulations. The emergence of Sierpi ski triangles is driven by a chemical transformation, i.e. the conversion of coordinative Au-thiolate to covalent thioether linkages, and can be further understood by Monte Carlo simulations. The great structural variance of TMB on Au(111) can on one hand be explained by the energetic equivalence of two binding motifs. On the other hand, the unexpected chemical transition even enhances the structural variance and results in thiol-derived covalent molecular architectures.3 KEYWORDS surface chemistry, on-surface synthesis, thiolate, thioether, fractals, STM, XPS, DFT, Monte CarloThe notorious affinity of thiols to gold is beneficial for molecular nano-science. 1 Important examples include ligation of gold nanoparticles, 2, 3 two probe conductance measurements of single molecules, [4][5][6][7] and surface functionalization of Au(111) by Self-Assembled Monolayers (SAMs). 8,9 All of these applications rely on anchoring via strong Au-thiolate bonds. Even though thiolate SAMs are widespread, structural details of the anchor bond were discussed controversially for a long time. Yet, a consensus seems to be reached insofar as Au-thiolate complexes formed with gold adatoms play an important role. 10 The promising properties of RSAu-SR linkages, in particular their electric conductance and their ability to form spontaneously on Au(111) motivated the present study with the aim to utilize these linkages for extended molecular nanostructures. To this end 1,3,5-tris(4-mercaptophenyl)benzene (TMB) as a threefold functionalized and suitable model compound for network formation is studied on Au(111).Owing to both the extended triphenylbenzene backbone and the three-point anchoring via thiolate-surface bonds, planar adsorption is anticipated as an important prerequisite for extended networks. In contrast to SAMs, where the prevalent monothiols adopt upri...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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From Au–Thiolate Chains to Thioether Sierpiński Triangles: The Versatile Surface Chemistry of 1,3,5-Tris(4-mercaptophenyl)benzene on Au(111)

et al. 2016

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“…The probe volume of the confocal microscope with the 20× objective is estimated to be ≈7.5 pL (on the basis of 1/ e 2 analysis. [ 72,73 ] Using the density of the liquid sample (i.e., 100 × 10 −3 M , corresponding to ≈6.02 × 10 22 molecules L −1…”

Section: Methodsmentioning

confidence: 99%

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Zhang

Liu

et al. 2015

Adv Materials Inter

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nanoporous lithography methods, [18][19][20][21] etc. However, these techniques are still expensive and complicated for the fabrication of high quality SERS substrates over large areas, thus resulting in high prices for commercial SERS substrates. Furthermore, most commercial SERS substrates can only work for individual excitation wavelengths, i.e., one particular product works at one or two excitation wavelengths only. [22][23][24][25][26][27][28] When one wants to identify anonymous trace molecules or mixed samples, multiple excitation wavelengths will be required. [29][30][31] In this case, different substrates have to be used for different wavelength excitation, which consumes more biological/chemical materials, substrates, and measurement time. This is an obvious disadvantage for conventional SERS substrates. On the contrary, the SERS EF is proportional to the product of the fi eld intensity enhancements at both excitation and Raman scattering wavelengths. It was predicted that the maximum SERS enhancement can be achieved when localized surface plasmon resonance is located between the excitation and Raman scattering wavelengths. [ 32 ] To realize higher EF, double-resonance SERS substrates were proposed to realize strong enhancements for excitation and Raman scattered signals simultaneously using expensive e-beam lithography processes. [ 23 ] Due to the narrowband absorption spectra for both resonant bands, the enhanced SERS signal is still limited within narrow spectral regions. To address this problem, broadband resonant nanostructures are highly desired. For instance, a relatively broadband 1D metal-dielectric-metal metasurface (i.e., ≈70% optical absorption from 420 to 550 nm) was fabricated using e-beam lithography to realize uniform enhancement for SERS sensing. [ 24 ] However, the top-down lithography technique imposed a signifi cant fabrication cost barrier for large-scale practical applications. In addition, 1D grating structures are polarization dependent which can only work for given polarization states (usually transverse magnetic polarization). To overcome these limitations, here we report an ultrabroadband super absorbing metasurface substrate that can enhance the SERS signal for excitation wavelengths in a broad spectral region using lithography-free processes. [ 33 ] Most frequently used excitation wavelengths for SERS (e.g., from 450 to 1100 nm [23][24][25][26][27][28]34 ] are all covered due to the broadband light trapping and fi eld concentration within deep subwavelength Most reported surface-enhanced Raman spectroscopy (SERS) substrates can work for individual excitation wavelengths only. Therefore, different substrates have to be used for different excitation wavelengths, which consumes more biological/chemical materials, substrates, and measurement time. Here, an ultrabroadband super absorbing metasurface that can work as a universal substrate for low cost and high performance SERS sensing is reported. Due to broadband light trapping and localized fi eld enhancement, this structure can...

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“…Whelan et al used XPS to investigate the gold-benzenethiol bond [153]. They used a Au(111) surface for their study, and confirmed the existence of Au-S bonds.…”

Section: Surface and Interfacial Elements And Moleculesmentioning

confidence: 99%

More power to X‐rays: New developments in X‐ray spectroscopy

Guo¹

2009

Laser & Photonics Reviews

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Recent developments in X-ray spectroscopy in the last decade are reviewed. A specific emphasis is placed on displaying the strong natural connection between X-ray spectroscopy and materials science. Brief explanations of several X-ray spectroscopic methods are given. X-ray spectroscopic instruments such as table-top X-ray sources are discussed in detail, whereas those employing synchrotron and other sources are briefly addressed. The spectroscopic methods and results from materials investigations are reviewed according to their positions in a 3D parameter space of time, length, and energy. New experimental measurements on atoms, molecules, nanomaterials, and bulk materials that include insulators, semiconductors, metals and magnetic materials using both static and time-resolved methods are reviewed.A typical table-top experimental setup to probe a sample using an optical pump (green color beam) -X-ray probe (purple color beam) technique. The X-ray pulses are produced by femtosecond optical pulses. Two exemplary data are displayed: One is direct imaging of plasmas generated from laser evaporation of a solid target (Imaging data) and the other is an X-ray absorption spectrum of a nickel sample (USEXAS data).

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HREELS, XPS, and Electrochemical Study of Benzenethiol Adsorption on Au(111)

Cited by 133 publications

References 70 publications

From Au–Thiolate Chains to Thioether Sierpiński Triangles: The Versatile Surface Chemistry of 1,3,5-Tris(4-mercaptophenyl)benzene on Au(111)

From Au–Thiolate Chains to Thioether Sierpiński Triangles: The Versatile Surface Chemistry of 1,3,5-Tris(4-mercaptophenyl)benzene on Au(111)

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

More power to X‐rays: New developments in X‐ray spectroscopy

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