Metal deposition onto a thiol-covered gold surface: A new approach

Ivanova, Valentina; Baunach, Thorsten; Kolb, Dieter M.

doi:10.1016/j.electacta.2005.05.047

Cited by 88 publications

(109 citation statements)

References 27 publications

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“…Recently, we have proposed another approach, 32 which is closely related to the work of Kolb and co-workers, [29][30][31] but provides stronger interaction between SAM and the formed metal layer by using dithiol. The adsorption energy of a thiolate group on Pt surface is approximately 65 kcal/mol 33 while that of pyridine with its nitrogen bound to Pt surface is around 18 kcal/mol.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

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Electrochemical deposition of metals (platinum or gold) only on top of an organothiolate, 1,4-benzenedimethanethiol (BDMT) or hexanedithiol (HDT), self-assembled monolayer (SAM) on a Au(111) substrate was achieved by electrochemical reduction of PtCl 4 2-or AuCl 4 -ion, which was preadsorbed on one free thiol end group of the dithiol SAM formed on a Au surface, in a metal-ion-free sulfuric acid solution at potentials more negative than the reduction potential of the metal ion. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) measurement after the reduction of preadsorbed PtCl 4 2-ion on BDMT/Au(111) electrode showed the presence of Pt not underneath but on top of the BDMT SAM. After a negative potential scan of the Pt/BDMT/Au(111) electrode to -1.30 V in 0.1 M KOH solution, a typical cyclic voltammogram of a clean Au(111) electrode was obtained, showing that the BDMT SAM with a Pt layer was reductively desorbed. These results proved that a Pt-BDMT SAM-Au substrate sandwich structure without a short circuit between the two metals was successfully constructed by this technique. Furthermore, a decanethiol (DT) monolayer was constructed on a Au layer, which was formed by the reduction of preadsorbed AuCl 4 -ion on HDT/Au(111) electrode. The formation of DT/Au/HDT/Au(111) structure was confirmed as two cathodic peaks corresponding to reductive desorption of DT from Au on top of the HDT/Au(111) at -0.97 V and that of Au/ HDT from Au(111) at -1.12 V were observed when potential was scanned negatively to -1.35 V.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

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“…In the cases of the complexes of metals of Fe(II), Co(II), Pt(II), Pd(II), and Rh(III) and 4-PyS-SAM, equilibrium between the solid phase and the solution phase was attained within 1 h, 16,17,24,25) indicating that the reaction time of 6 h for U(VI) association with 4-PyS-SAM was long enough to attain equilibrium. The acidity (pK) of acetic acid, oxalic acid, and oxalic acid mono-anions are 4.56, 1.0, and 3.38, respectively, 26) indicating that about 10 mM acetic acid becomes mono-anionic and 40 mM oxalate becomes di-anionic at pH 4.0.…”

Section: Discussionmentioning

confidence: 99%

Sorption of U(VI) on the 4-Mercaptopyridine Self-Assembled Monolayer

Nankawa

Ozaki

Francis

et al. 2008

J. Nucl. Sci. Technol.

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The sorption of U(VI) on the 4-mercaptopyridine self-assembled monolayer (4-PyS-SAM) on Au(111) was studied by cyclic voltammetry. Cyclic voltammograms (CVs) of the 4-PyS-SAM working electrode were obtained by contact with 1 mM UO 2 (NO 3 ) 2 solution, 1 mM UO 2 (NO 3 ) 2 and 50 mM acetic acid solution, or 1 mM UO 2 (NO 3 ) 2 and 50 mM oxalic acid solution for 6 h at pH 4. The reduction current of U(VI) to U(V) was detected in the CV. The CV of the U(VI) associated 4-PyS-SAM after transport to U(VI)-free 0.1 M NaClO 4 solution showed that the reduction current was detected in the cases of UO 2 (NO 3 ) 2 and U(VI)-acetate, but not in the case of U(VI)-oxalate solution, indicating that U(VI) was adsorbed on the 4-PyS-SAM from the UO 2 (NO 3 ) 2 and U(VI)-acetate solutions, but not from U(VI)-oxalate solution. These results suggest that stability of U(VI)-4-PyS-SAM is not so high that U(VI)-4-PyS-SAM cannot be formed in the presence of 50 mM oxalate.

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“…[7][8][9][10] Photoelectron spectroscopy together with density functional theory (DFT) taking into account all contributing parts of the molecular junction finally allowed analysis of its structural setup and its electronic properties. Angle-resolved X-ray photoelectron spectroscopy (XPS) reveals that the 4-ATP SAM actually consists of a minimum of two molecular layers.…”

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confidence: 99%

Chemical Interactions at Metal/Molecule Interfaces in Molecular Junctions—A Pathway Towards Molecular Recognition

et al. 2009

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Small organic molecules as potential building-blocks for future nanoelectronic devices [1][2][3][4][5] will require new types of sensors able to identify/quantify molecules in appropriate solutions on a single-molecule level. Recently, an elegant new method has been proposed [6] that allows detection of small aromatic units like 4-aminothiophenol (4-ATP) molecules by measuring the tunneling resistance between two metal electrodes separated by a short distance (a few nanometers). While, from a simple point of view, an increase in conductivity should be expected because of the bridging of the tunnelling gap by one or more molecules (thus offering molecular orbitals as additional transport channels), a decreased conductivity was observed experimentally with a reduction factor that depended on the type of molecule present in the solution. Here, we report on combined experimental and theoretical efforts aimed at unravelling this phenomenon by studying the electronic properties of one of the metal electrodes in such a molecular junction.For this purpose, a 4-ATP self-assembled monolayer (SAM) has been prepared on top of a Au(111) crystal, which, in a second step, has been metallized by a nearly closed Pd overlayer of monoatomic height by means of a recently developed electrochemical approach. [7][8][9][10] Photoelectron spectroscopy together with density functional theory (DFT) taking into account all contributing parts of the molecular junction finally allowed analysis of its structural setup and its electronic properties. Angle-resolved X-ray photoelectron spectroscopy (XPS) reveals that the 4-ATP SAM actually consists of a minimum of two molecular layers. Most importantly, using ultraviolet photoelectron spectroscopy (UPS) and DFT simulations, strong chemical interactions between the metal overlayer and the amino groups are found to play a decisive role in determining the overall electronic properties, and thus the transport properties of the SAM/metal contact, as will be demonstrated in the following.It is well-known that 4-ATP has a strong tendency to form multilayers on Au(111), which lead to scanning tunnelling microscopy (STM) images with considerable height variations and of blurred contrast when it comes to molecular-scale resolution.[11] Even for highly diluted solutions (sub-millimolar concentrations of the 4-ATP), more than just one layer is generally formed. On the other hand, reductive desorption of thiols from gold surfaces is known to occur at electrode potentials negative of À0.1 V vs. standard calomel electrode (SCE), which may be considered an appropriate means for desolving any thiol in excess of the first layer.[12] In Figure 1 cyclic voltammograms are shown for Au(111) in 0.1 M H 2 SO 4 , after the electrode had been immersed for 15 min in a 0.1 Â 10 À3 M 4-ATP/0.1 M H 2 SO 4 modification solution. While the first cycle (dash-dotted line, start at þ0.2 V vs. SCE in the negative direction) was restricted to the stability range of the 4-ATP adlayer, i.e., 0 and þ0.4 V, the second cycle (solid line)...

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Metal deposition onto a thiol-covered gold surface: A new approach

Cited by 88 publications

References 27 publications

Electrochemical Metal Deposition on Top of an Organic Monolayer

Electrochemical Metal Deposition on Top of an Organic Monolayer

Sorption of U(VI) on the 4-Mercaptopyridine Self-Assembled Monolayer

Chemical Interactions at Metal/Molecule Interfaces in Molecular Junctions—A Pathway Towards Molecular Recognition

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