Creation of Low-Coordination Gold Sites on Au(111) Surface by 1,4-phenylene Diisocyanide Adsorption

Boscoboinik, J. Anibal; Kestell, John; Garvey, Michael; Weinert, M.; Tysoe, Wilfred T.

doi:10.1007/s11244-011-9642-9

Cited by 40 publications

(75 citation statements)

References 57 publications

(105 reference statements)

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“…PDI Binding and Morphology on Au(111). The long 1-D chains observed in the STM image in Figure 2b and c are similar to those recently reported by Boscoboinik et al, for PDI deposited and imaged at 300 K on a Au(111) surface at both very low coverage (∼0.004 ML) 24 and saturated coverage 25. In their…”

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confidence: 90%

Adsorption Structures and Electronic Properties of 1,4-Phenylene Diisocyanide on the Au(111) Surface

et al. 2011

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The adsorption structures and electronic properties of 1,4-phenylene diisocyanide (PDI) on a Au(111) surface have been studied using temperature programmed desorption (TPD), two-photon photoemission (2PPE), and scanning tunneling microscopy (STM). As deposited at 95 K, PDI molecules form disordered islands and short one-dimensional chains on Au(111) terraces. The work function decreases with increasing PDI coverage, and an occupied electronic state appears at 0.88 eV below the Fermi level. Annealing to 300 K causes the PDI molecules to reorganize on the surface and form ordered, one-dimensional molecular chains that extend for many tens of nanometers across the Au(111) terraces. The repeating structure of the molecular chains is consistent with a recently proposed [−Au–PDI−] n structure in which PDI molecules lie parallel to the surface and are interconnected by Au adatoms released from the Au(111) surface. The formation of the molecular chains is accompanied by a large drop in the work function which we attribute to an increase in the number and magnitude of interfacial dipoles. The electronic structure of the molecular chains is also characterized by occupied and unoccupied states at −0.88 eV below and +3.32 eV above the Fermi level, respectively. The latter are most prominent after annealing a PDI/Au(111) surface to 300 K, indicating that they are associated with interfacial states of the one-dimensional molecular chains.

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confidence: 90%

Adsorption Structures and Electronic Properties of 1,4-Phenylene Diisocyanide on the Au(111) Surface

et al. 2011

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“…[15][16][17] The relatively short (B1.1 nm) repeat distance between gold atoms in the oligomer suggests the possibility of being able to chemically bond between gold nanoparticles with various separations by incorporating a number of repeat units until the gap is bridged. PDI has been previously proposed as a prototypical molecular electronic component, 4,6,[18][19][20][21] and theory suggests that PDI is a suitable candidate for device applications.…”

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confidence: 99%

“…S2 (ESI †). 15 A maximum activation energy of B0.8 eV is estimated for this process by assuming that the partition functions in the initial and transition states are equal yielding an Arrhenius pre-exponential factor (kT/h) of B10 13 s À1 . In fact, the hopping rate could be higher if more events had occurred that were not observed within the time resolution of our experiment.…”

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confidence: 99%

Linking gold nanoparticles with conductive 1,4-phenylene diisocyanide–gold oligomers

et al. 2013

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A major challenge to fabricating molecular electronic circuits 1 is the difficulty of simultaneously chemically bonding molecular components to two metal electrodes. This can be accomplished by adjusting the electrode separation to match the molecular dimensions using break junctions 2-5 or by using a sharp tip to vary the electrode-surface spacing. 6 Such approaches provide detailed information on molecular conduction, but are not easily extended to planar systems required for a realistic circuit. 7Molecularly linked nanoparticles have been synthesized in solution and deposited onto surfaces 7,8 but the location of the nanoparticles in the circuit is dictated by the cross-linking structure. Ordered assemblies have been formed from functionalized nanoparticles but they are often not covalently connected. Finally, the length of the molecular linker can be matched to the nanoparticle spacing but requires the molecular size to be tailored to the separation of the nanoparticles. 10An alternative strategy is proposed based on recent observations that molecules that bind strongly to metals with low cohesive energies such as gold or copper can oligomerize by extracting metal atoms from the substrate.11-14 An example of this is the lateral self-assembly of 1,4-phenylene diisocyanide (PDI) on Au(111) that forms -(Au-PDI) n -oligomers comprising long, one-dimensional chains by extracting low-coordination gold atoms from surface defect sites. [15][16][17] The relatively short (B1.1 nm) repeat distance between gold atoms in the oligomer suggests the possibility of being able to chemically bond between gold nanoparticles with various separations by incorporating a number of repeat units until the gap is bridged. PDI has been previously proposed as a prototypical molecular electronic component, 4,6,[18][19][20][21] and theory suggests that PDI is a suitable candidate for device applications. 22This lateral self-assembly is explored by measuring the conductivity of a gold nanoparticle film on mica that has been exposed to PDI. Evaporating gold films on mica (and other insulating substrates)23-28 provides a simple method for growing isolated nanoparticles with different spacings merely by ensuring that the gold film thickness remains below a critical value, above which a continuous film is formed. The success of this approach relies on the oligomers being sufficiently mobile to bridge between nanoparticles. This mobility is illustrated in Fig. 1, which displays a typical series of 15 consecutive STM images (taken 53 seconds apart) of a saturated layer of Au-PDI chains on Au (111) showing the repeated lateral motion of an entire chain, where a line is drawn to highlight the chain motion, showing nine hopping events corresponding

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“…This is longer than that observed for PDI chains on Au(111), 11.7±0.2 Å, by approximately the length of an extra phenyl ring (see Figure 3). 17,18,24 The correlation between the monomer length and molecular dimensions supports an adsorption geometry in which BPDI molecules lie parallel (or nearly so) to the surface. Since abutting -NC terminal groups are not likely to be chemically linked, diisocyanide chain formation would require a common surface binding site for both terminal -NC groups.…”

Section: A Adsorption Structuresmentioning

confidence: 76%

“…13 By contrast, recent scanning tunneling microscopy (STM) experiments showed that 1,4-phenyldiisocyanide (PDI) deposited from the vapor onto a Au(111) surface at room temperature forms one-dimensional (1D) molecular chain structures. 17,18 The proposed adsorption model for this molecular chain involves alternating PDI molecules and Au adatoms, i.e., a repeating [-PDI-Au-] monomer unit. In this structure, the PDI molecules lie flat on the surface and are bonded at each end to Au-adatoms, which originate from step edges or the Au(111) surface reconstruction.…”

Section: Introductionmentioning

confidence: 99%

Characterization of one-dimensional molecular chains of 4,4′-biphenyl diisocyanide on Au(111) by scanning tunneling microscopy

Zhou

Zahl

et al. 2015

The Journal of Chemical Physics

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The morphology and electronic structure of vapor deposited 4,4'-biphenyldiisocyanide (BPDI) on a Au(111) surface were investigated using variable-temperature scanning tunneling microscopy. When deposited at room temperature, BPDI molecules form one-dimensional molecular chains similar to that recently observed for the structurally related 1,4-phenyl diisocyanide (PDI). Compared to PDI, the longer periodicity for the BPDI molecular chains is consistent with the addition of a second phenyl ring and supports a structural model in which the BPDI molecules lie parallel to the surface and interconnected by Au-adatoms. The molecular chains are mostly aligned along the 11̄0 direction of the Au(111) substrate, but exhibit frequent changes in angle that are consistent with directions between fcc and hcp three-fold hollow sites. Dispersion-corrected density functional theory calculations for one-dimensional chains of BPDI molecules bound end-to-end via their isocyanide groups to Au-adatoms reproduce the observed periodicity of the chains and show that this morphology is energetically favored over upright binding with one free -NC group. The spatially resolved conductance (dI/dV) map for BPDI on Au(111) exhibits a feature centered at -0.67 eV below the Fermi level which are delocalized along the chain with maxima at the Au-adatom and biphenyl positions. This occupied resonant feature is close to that previously observed for the PDI in both photoemission and conductance measurements and is attributed to an occupied interfacial state resulting from BPDI-Au interactions.

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Creation of Low-Coordination Gold Sites on Au(111) Surface by 1,4-phenylene Diisocyanide Adsorption

Cited by 40 publications

References 57 publications

Adsorption Structures and Electronic Properties of 1,4-Phenylene Diisocyanide on the Au(111) Surface

Adsorption Structures and Electronic Properties of 1,4-Phenylene Diisocyanide on the Au(111) Surface

Linking gold nanoparticles with conductive 1,4-phenylene diisocyanide–gold oligomers

Characterization of one-dimensional molecular chains of 4,4′-biphenyl diisocyanide on Au(111) by scanning tunneling microscopy

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