Reproducible Measurement of Single-Molecule Conductivity

Cui, Xiaodong; Primak, A.; Zárate, Xristo; Tomfohr, John K.; Sankey, Otto F.; Moore, Ana L.; Moore, Thomas A.; Gust, Devens; Harris, Gari; Lindsay, Stuart

doi:10.1126/science.1064354

Cited by 1,258 publications

(1,207 citation statements)

References 21 publications

Supporting

Mentioning

1,147

Contrasting

Unclassified

Order By: Relevance

“…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.…”

Section: Carlomentioning

confidence: 99%

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

View full text Add to dashboard Cite

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...

show abstract

Section: Carlomentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…Dithiol SAMs are also used for attracting and fixing the metal nanoparticles on the surface from a solution. [11][12][13][14] Formation of a metal layer on top of an SAM by electrochemical deposition has several advantages over vacuum deposition. For example, electrochemical deposition is less complex, less expensive, and easier to control.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

View full text Add to dashboard Cite

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.

show abstract

“…This may be attributable to intrinsic changes in electronic coupling through the thiol link for different local link configurations [3]. Experiments are performed using diverse platforms to probe either the conductance of one or a few molecules forming a circuit [4][5][6][7][8][9][10][11][12][13][14] or to probe a small patch of molecules forming an interface in an ensemble measurement [15][16][17]. While progress has been made in comparing different approaches [18], significant puzzles remain, for instance the substantial differences that have been observed between ensemble and single molecule measurements for the same species [19].…”

Section: Introductionmentioning

confidence: 99%

Amine-linked single-molecule circuits: systematic trends across molecular families

Hybertsen¹,

Venkataraman²,

Klare³

et al. 2008

J. Phys.: Condens. Matter

147

196

View full text Add to dashboard Cite

Abstract.A comprehensive review is presented of single molecule junction conductance measurements across families of molecules measured while breaking a gold point contact in a solution of molecules with amine end groups. A theoretical framework unifies the picture for the amine-gold link bonding and the tunnel coupling through the junction using Density Functional Theory based calculations. The reproducible electrical characteristics and utility for many molecules is shown to result from the selective binding between the gold electrodes and amine link groups through a donor-acceptor bond to undercoordinated gold atoms. While the bond energy is modest, the maximum force sustained by the junction is comparable to, but less than, that required to break gold point contacts. The calculated tunnel coupling provides conductance trends for all 41 molecule measurements presented here, as well as insight into the variability of conductance due to the conformational changes within molecules with torsional degrees of freedom. The calculated trends agree to within a factor of two of the measured values for conductance ranging from 10 -7 G 0 to 10 -2 G 0 , where G 0 is the quantum of conductance (2e 2 /h).

show abstract

Reproducible Measurement of Single-Molecule Conductivity

Cited by 1,258 publications

References 21 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)

Electrochemical Metal Deposition on Top of an Organic Monolayer

Amine-linked single-molecule circuits: systematic trends across molecular families

Contact Info

Product

Resources

About