A computational study of surface diffusion of C60 on pentacene

Cantrell, Rebecca; Clancy, Paulette

doi:10.1016/j.susc.2008.09.027

Cited by 52 publications

(63 citation statements)

References 30 publications

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“…The MM3 potential is an explicit all-atom potential similar to other explicit potentials such as OPLS-AA, Dreiding, CHARMM, etc. 27,28,37 The MM3 potential has been shown, by us and others, [38][39][40][41][42][43] to describe hydrocarbons quite accurately, 36 in many cases, in good agreement with ab initio calculations. MM3 incorporates stretching, bending, and torsional energies, as well as the van der Waals interaction energies based on phenomenologically determined parameters.…”

Section: Intermolecular Potential Modelsmentioning

confidence: 83%

Explicit all-atom modeling of realistically sized ligand-capped nanocrystals

Kaushik

Clancy

2012

The Journal of Chemical Physics

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We present a study of an explicit all-atom representation of nanocrystals of experimentally relevant sizes (up to 6 nm), "capped" with alkyl chain ligands, in vacuum. We employ all-atom molecular dynamics simulation methods in concert with a well-tested intermolecular potential model, MM3 (molecular mechanics 3), for the studies presented here. These studies include determining the preferred conformation of an isolated single nanocrystal (NC), pairs of isolated NCs, and (presaging studies of superlattice arrays) unit cells of NC superlattices. We observe that very small NCs (3 nm) behave differently in a superlattice as compared to larger NCs (6 nm and above) due to the conformations adopted by the capping ligands on the NC surface. Short ligands adopt a uniform distribution of orientational preferences, including some that lie against the face of the nanocrystal. In contrast, longer ligands prefer to interdigitate. We also study the effect of changing ligand length and ligand coverage on the NCs on the preferred ligand configurations. Since explicit allatom modeling constrains the maximum system size that can be studied, we discuss issues related to coarse-graining the representation of the ligands, including a comparison of two commonly used coarse-grained models. We find that care has to be exercised in the choice of coarse-grained model. The data provided by these realistically sized ligand-capped NCs, determined using explicit all-atom models, should serve as a reference standard for future models of coarse-graining ligands using united atom models, especially for self-assembly processes.

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Section: Intermolecular Potential Modelsmentioning

confidence: 83%

Explicit all-atom modeling of realistically sized ligand-capped nanocrystals

Kaushik

Clancy

2012

The Journal of Chemical Physics

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“…We have used this model extensively to study the energetics and structural characteristics of an array of small organic semiconducting molecules including the acenes, rubrene, DIP, sexiphenyl and C 60 [9,10] and have confidence in its ability to model conjugated systems. For instance, we conducted an extensive survey of twelve Density Functional Theory models, as well as the MM3 and MM3-π models for biphenyl and eight models (four DFT and four semi-empirical models) for the sexiphenyl molecule.…”

Section: Intermolecular Potential Modelsmentioning

confidence: 99%

Effects of Odd–Even Side Chain Length of Alkyl-Substituted Diphenylbithiophenes on First Monolayer Thin Film Packing Structure

et al. 2013

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Because of their preferential two-dimensional layer-by-layer growth in thin films, 5,5′bis(4-alkylphenyl)-2,2′-bithiophenes (P2TPs) are model compounds for studying the effects of systematic chemical structure variations on thin-film structure and morphology, which in turn, impact the charge transport in organic field-effect transistors. For the first time, we observed, by grazing incidence X-ray diffraction (GIXD), a strong change in molecular tilt angle in a monolayer of P2TP, depending on whether the alkyl chain on the P2TP molecules was of odd or even length. The monolayers were deposited on densely packed ultrasmooth self-assembled alkane silane modified SiO2 surfaces. Our work shows that a subtle change in molecular structure can have a significant impact on the molecular packing structure in thin film, which in turn, will have a strong impact on charge transport of organic semiconductors. This was verified by quantum-chemical calculations that predict a corresponding odd–even effect in the strength of the intermolecular electronic coupling.

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“…MM3 incorporates stretching, bending, and torsional energies, as well as the van der Waals interaction energies based on phenomenologically determined parameters. We have used this model extensively to study the energetics and structural characteristics of an array of small organic molecules including the acenes, rubrene, DIP, sexiphenyl and C 60 [9,10] and have confidence in its ability to model conjugated systems. Our most recent study involved an extensive survey of twelve Density Functional Theory models, as well as the MM3 and MM3-π models for biphenyl and eight models (four DFT and four semi-empirical models) for the sexiphenyl molecule.…”

Section: B Intermolecular Potential Modelsmentioning

confidence: 99%

“…There have been several molecular-level computational studies of SAMs, some of which are particularly relevant to the studies in this paper [1,[4][5][6][7][8][9][10]. Yamamoto et al studied the influence of hydrogen bond conformations of alkylsilane SAMs using molecular mechanics and Molecular Dynamics simulations [1].…”

Section: Introductionmentioning

confidence: 99%

Trapping dynamics of diindenoperylene (DIP) in self-assembled monolayers using molecular simulation

Kaushik

Clancy

2011

Surface Science

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All-atom Molecular Dynamics simulation methods employing a well-tested intermolecular potential model, MM3, demonstrate the extent of the propensity for diindenoperylene (DIP) molecules to insert between molecules of a self-assembled monolayer (SAM) during a deposition process intended to grow a thin film of this organic semiconductor molecule onto the surface of self-assembled monolayers. The tendency to insert between SAM molecules is fairly prevalent at normal growth temperatures and conditions, but is most strongly dependent on the density and the nature of the SAM. We posit the existence of an optimal density to favor surface adsorption over insertion for this system. DIP is less likely to insert in fluorinated SAMs, like FOTS, than its unfluorinated analog, OTS. It is also less likely to insert between shorter SAMs (e.g., less insertion in OTS than ODTS). Very short length, surface-coating molecules, like HDMS, are more likely to scatter energetic incoming DIP molecules with little insertion on first impact (depending on the incident energy of the DIP molecule). Grazing angles of incidence of the depositing molecules generally favor surfaceadsorption, at least in the limit of low coverage, but are shown to be dependent on the nature of the SAM. The validity of these predictions is confirmed by comparison of the predicted sticking coefficients of DIP at a variety of incident energies on OTS, ODTS, and FOTS SAMs with results obtained experimentally by Engstrom et al. The simulation predictions of the tendency of DIP to insert can be explained, in large part, in terms of binding energies between SAM and DIP molecules. However, we note that entropic and stochastic events play a role in the deposition outcomes.

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A computational study of surface diffusion of C60 on pentacene

Cited by 52 publications

References 30 publications

Explicit all-atom modeling of realistically sized ligand-capped nanocrystals

Explicit all-atom modeling of realistically sized ligand-capped nanocrystals

Effects of Odd–Even Side Chain Length of Alkyl-Substituted Diphenylbithiophenes on First Monolayer Thin Film Packing Structure

Trapping dynamics of diindenoperylene (DIP) in self-assembled monolayers using molecular simulation

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