Symmetry-Break-Induced Variation Of Energy-Level Degeneracy Observed On Individual Molecules By Low-Temperature STM

Mautes, D; Zhang, H.; Hartmann, U.

doi:10.1063/1.1639811

Cited by 2 publications

(5 citation statements)

References 16 publications

(18 reference statements)

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“…The PPh 3 /Au(111) system appears to be significantly different from other commonly used self-assembly reagents such as alkanethiols, thioethers, and fullerenes. In clear contrast to earlier reports, 32 we find that PPh 3 selfassembles to form two highly ordered surface structures. More importantly the adsorption of PPh 3 causes the partial lifting of Au's native reconstruction via the ejection of Au atoms, which become kinetically trapped in the form of pure, monolayer-high Au(111) (1Â1) islands, which remain stable up to high temperatures.…”

contrasting

confidence: 99%

“…Our results reveal the complex self-assembly behavior of PPh 3 , a common ligand in organic, organometallic, and metal nanoparticle synthesis on Au(111). In contrast to other popular capping agents such as thiols, the surface chemistry of this important species has to date gone almost completely unexamined. − We find that PPh 3 adsorption perturbs the Au(111) surface’s native herringbone reconstruction but stops short of etch pit formation commonly seen with thiol SAMs on Au. The packing was highly ordered, and high-resolution STM imaging shows submolecular resolution indicating that, in the most common packing arrangement, the molecules are upright and all three phenyl groups are imaged with the same intensity.…”

Section: Discussionmentioning

confidence: 83%

“…Using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), Mautes et al . studied the adsorption of PPh 3 on Au(111) by spin-coating from dichloromethane solution but did not observe any ordered structure within the monolayer . More recently Xu et al .…”

mentioning

confidence: 99%

“…Using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), Mautes et al studied the adsorption of PPh 3 on Au(111) by spin-coating from dichloromethane solution but did not observe any ordered structure within the monolayer. 32 More recently Xu et al reported on the self-assembly of calix [4]arene dimelamine derivatives on Au(111). 37 These molecules consist of a central head formed from a calix [4]arene moiety, which is connected to two identical arms, starting at a melamine unit and terminating in a PPh 3 group.…”

mentioning

confidence: 99%

“…Despite the number of studies on the electronic properties, stability, and catalytic behavior of PPh 3 -stabilized Au clusters, our knowledge of the interaction of PPh 3 with flat Au surfaces, in the absence of solvents, is rather limited. − Steiner et al . were among the first to study surface-bound PPh 3 .…”

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confidence: 99%

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Molecular-Scale Surface Chemistry of a Common Metal Nanoparticle Capping Agent: Triphenylphosphine on Au(111)

2012

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Phosphine-stabilized Au clusters have been extensively studied and are used in various applications due to their unique structural, catalytic, and electronic properties. Triphenylphosphine (PPh(3)) is a key stabilizing ligand in the synthesis of Au nanoclusters. Despite its intense use in nanoparticle synthesis protocols, little is known regarding its surface chemistry, monolayer structure, density, and packing arrangement, all of which are important descriptors of functionality. Here, in contrast to sparse earlier investigations, we report that PPh(3) forms very ordered structures on Au(111). Atomic-scale imaging reveals that monolayer formation is accompanied by a partial lifting of the Au(111) surface reconstruction and ejection of extra Au atoms in the surface layer. Interestingly, these atoms are trapped and stabilized as two-dimensional Au nanoislands within the molecular layer. This behavior is in contrast to thiols, also common capping agents, which tend to remove Au atoms beyond those extra atoms present in the native reconstruction and form vacancy islands on the surface. Our data illustrate PPh(3)'s milder reactivity and reveal a new picture of its packing structure. These results shed new light on the surface chemistry of this important ligand for organic, organometallic, and nanoparticle synthesis.

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confidence: 99%

Section: Discussionmentioning

confidence: 83%

mentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Molecular-Scale Surface Chemistry of a Common Metal Nanoparticle Capping Agent: Triphenylphosphine on Au(111)

2012

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Negative differential resistance and nonclassical capacitive behaviour in networks of metal clusters

Zhang¹,

Mautes²,

Hartmann³

2007

Nanotechnology

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Monolayers of small metal clusters of type Au55[P(C6H5)3]12Cl6 were investigated with a low-temperature ultrahigh vacuum scanning tunnelling microscope. Apart from the usual charge-quantization phenomena, such as Coulomb blockade and staircase, negative differential resistance was observed by performing measurements at distinct locations on the cluster layers. The latter phenomenon can be understood from a ‘gate’ effect caused by neighbouring clusters and involving a nonclassical behaviour of the capacitances generated by the nanoscale tunnel junctions.

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Symmetry-Break-Induced Variation Of Energy-Level Degeneracy Observed On Individual Molecules By Low-Temperature STM

Cited by 2 publications

References 16 publications

Molecular-Scale Surface Chemistry of a Common Metal Nanoparticle Capping Agent: Triphenylphosphine on Au(111)

Molecular-Scale Surface Chemistry of a Common Metal Nanoparticle Capping Agent: Triphenylphosphine on Au(111)

Negative differential resistance and nonclassical capacitive behaviour in networks of metal clusters

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