Development of a semiempirical potential for simulations of thiol–gold interfaces. Application to thiol-protected gold nanoparticles

Olmos-Asar, Jimena A.; Rapallo, Arnaldo; Mariscal, Marcelo M.

doi:10.1039/c0cp02921a

Cited by 32 publications

(61 citation statements)

References 43 publications

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“…Other studies 17,[26][27][28][29][30][31][32][33] indicate that surface reconstruction may play an important role during the SAM formation with the presence of vacancies or single adatoms sitting on the flat surface. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 Experiment [34][35][36][37][38][39][40] and simulations [41][42][43][44][45][46][47][48][49][50] show marked differences between the SAMs on flat surface and nanocrystals. Thus, the average surface per thiolate is about 10 to 20 % smaller for Au NCs 35,<...>…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of Self-Assembled Monolayers on Octahedral and Cubic Gold Nanocrystals

et al. 2015

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International audienceThis paper reports on a molecular dynamics investigation of the molecular organization of alkanethiolates (from ethane to dodecanethiolate) on octahedral and cubic gold nanocrystals with diameters up to 10 nm. We show that the average surface per adsorbed thiolate only slightly depends on the nanocrystal shape and the alkane chain length. Two different organizations of thiolates are observed on the facet centers and edges of octahedral nanocrystals, while on cubic nanocrystals only one appears. This explains the closer distance between thiolates on the edges of octahedral nanocrystals, which is not observed for nanocubes. The enhanced surface coverage of thiolates on nanocrystals is explained by the new organization for octahedral nanocrystals and can be attributed to the occupation of adsorption sites on the edges for cubic nanocrystals. Small differences observed in the molecular organizations on icosahedral and octahedral nanocrystals can be mainly explained by the larger facets of the latter ones

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Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of Self-Assembled Monolayers on Octahedral and Cubic Gold Nanocrystals

et al. 2015

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“…31 The parameters obtained are D e = 1.2746 eV, r e = 2.2898 Å, and α = 1.47 Å −1 . To represent the interaction between head groups of butanethiolate (thiolate groups) and palladium, the new semiempirical potential previously developed by the authors 32 was parametrized by means of DFT calculations. The main characteristic of this potential is that bond orders (BOs) of the interacting species are considered to distinguish different geometries of adsorption using distinct parameters as a function of the coordination.…”

Section: ■ Experimental and Theoretical Methodsmentioning

confidence: 99%

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

et al. 2014

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The role that protecting molecules have on the way that palladium atoms arrange themselves in nanoparticles prepared at room temperature was studied by the analysis of aberration-corrected scanning transmission electron microscopy images and atomistic Langevin dynamics simulations. It was found that the arrangement of Pd atoms is less ordered in thiolate-protected nanoparticles than in amine-protected ones. The experimental and theoretical data showed that the disorder in ∼3 nm thiolate-protected particles is promoted by the strong S−Pd bond in the sulfide layer that surrounds the nanoparticles. ■ INTRODUCTIONThe unique properties of thiolate self-assembled monolayers (SAMs) have provoked great interest in these assemblies, especially for their role in the stability and interfacial properties of thiolate-protected noble-metal nanoparticles (NPs).1,2 Gold nanoparticles are among the most studied metal nanoparticles, to the point of being considered the de facto model system in this field of research.3,4 However, some properties of other metals can be very different from those of gold, and the case of palladium is an example that fulfills this statement. For instance, the adsorption of alkanethiols on planar palladium surfaces produces a sulfide layer (with submonolayer coverage) lying at the interface between palladium and thiolate moieties. 5−7Density functional theory (DFT) calculations show that the sulfide layer comes from the S−C bond scission caused by a charge transfer from the palladium d band to antibonding thiolate orbitals. 7 In addition, it was recently shown that the chemical composition of the surface of alkanethiolate-protected palladium nanoparticles is very similar to that of alkanethiolatemodified bulk palladium: Pd(0) cores are surrounded by a submonolayer of sulfide species, which are protected by alkanethiolates. 8−10 Despite the fact that these particles have very interesting properties that can be exploited in catalysis 11 and sensing, 12 their detailed structure has been barely studied. Indeed, even in recent studies, the already known 5,8 chemical nature of the Pd−thiolate interface is ignored. 11−14It is well-known that thiolate species produce a reconstruction of the gold surface both in planar substrates 15 and in nanoparticles. 16 Results from molecular simulations suggest that the influence of the capping molecule can also reach deeper atomic layers in gold nanoparticles smaller than 2 nm. 17,18 In the case of planar palladium, DFT calculations show that when only thiolates are adsorbed on the surface, there is no reordering of the metal atoms in the first layers; 7,13 however, when sulfide is incorporated as an adsorbate, a considerable surface reconstruction takes place. This behavior is attributed to

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“…At each approaching step the internal energy of the system is computed using the interatomic potential of reference. 36 …”

Section: Theoretical Calculationsmentioning

confidence: 99%

Structural order in ultrathin films of the monolayer protected clusters based upon 4 nm gold nanocrystals: an experimental and theoretical study

Bhattarai

Khanal

Bahena

et al. 2014

Phys. Chem. Chem. Phys.

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The structural order in ultrathin films of monolayer protected clusters (MPCs) is important in a number of application areas but can be difficult to demonstrate by conventional methods, particularly when the metallic core dimension, d, is in the intermediate size-range, 1.5 < d < 5.0 nm. Here, improved techniques for the synthesis of monodisperse thiolate-protected gold nanoparticles have made possible the production of dodecane-thiolate saturated ~ 4 ± 0.5 nm Au clusters with single-crystal core structure and morphology. An ultrathin ordered film or superlattice of these nanocrystal-core MPCs is prepared and investigated using aberration corrected scanning/transmission electron microscopy (STEM) which allowed imaging of long-range hexagonally ordered superlattices of the nanocrystals, separated by the thiolate groups. The lattice constants determined by direct imaging are in good agreement with those determined by small-angle electron diffraction. The STEM image revealed the characteristic grain boundary (GB) with sigma (Σ) 13 in the interface between two crystals. The formation and structures found are interpreted on the basis of theoretical calculations employing molecular dynamics (MD) simulations and coarse-grained (CG) approach.

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Development of a semiempirical potential for simulations of thiol–gold interfaces. Application to thiol-protected gold nanoparticles

Cited by 32 publications

References 43 publications

Atomistic Simulations of Self-Assembled Monolayers on Octahedral and Cubic Gold Nanocrystals

Atomistic Simulations of Self-Assembled Monolayers on Octahedral and Cubic Gold Nanocrystals

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

Structural order in ultrathin films of the monolayer protected clusters based upon 4 nm gold nanocrystals: an experimental and theoretical study

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