Solvent-driven symmetry of self-assembled nanocrystal superlattices-A computational study

Handle URI:
http://hdl.handle.net/10754/599669
Title:
Solvent-driven symmetry of self-assembled nanocrystal superlattices-A computational study
Authors:
Kaushik, Ananth P.; Clancy, Paulette
Abstract:
The preference of experimentally realistic sized 4-nm facetted nanocrystals (NCs), emulating Pb chalcogenide quantum dots, to spontaneously choose a crystal habit for NC superlattices (Face Centered Cubic (FCC) vs. Body Centered Cubic (BCC)) is investigated using molecular simulation approaches. Molecular dynamics simulations, using united atom force fields, are conducted to simulate systems comprised of cube-octahedral-shaped NCs covered by alkyl ligands, in the absence and presence of experimentally used solvents, toluene and hexane. System sizes in the 400,000-500,000-atom scale followed for nanoseconds are required for this computationally intensive study. The key questions addressed here concern the thermodynamic stability of the superlattice and its preference of symmetry, as we vary the ligand length of the chains, from 9 to 24 CH2 groups, and the choice of solvent. We find that hexane and toluene are "good" solvents for the NCs, which penetrate the ligand corona all the way to the NC surfaces. We determine the free energy difference between FCC and BCC NC superlattice symmetries to determine the system's preference for either geometry, as the ratio of the length of the ligand to the diameter of the NC is varied. We explain these preferences in terms of different mechanisms in play, whose relative strength determines the overall choice of geometry. © 2012 Wiley Periodicals, Inc.
Citation:
Kaushik AP, Clancy P (2012) Solvent-driven symmetry of self-assembled nanocrystal superlattices-A computational study. Journal of Computational Chemistry 34: 523–532. Available: http://dx.doi.org/10.1002/jcc.23152.
Publisher:
Wiley-Blackwell
Journal:
Journal of Computational Chemistry
KAUST Grant Number:
KUS-C1-018-02
Issue Date:
29-Oct-2012
DOI:
10.1002/jcc.23152
PubMed ID:
23109263
Type:
Article
ISSN:
0192-8651
Sponsors:
Contract/grant sponsor: King Abdullah University of Science and Technology (KAUST); contract/grant number: KUS-C1-018-02.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorKaushik, Ananth P.en
dc.contributor.authorClancy, Pauletteen
dc.date.accessioned2016-02-28T06:07:08Zen
dc.date.available2016-02-28T06:07:08Zen
dc.date.issued2012-10-29en
dc.identifier.citationKaushik AP, Clancy P (2012) Solvent-driven symmetry of self-assembled nanocrystal superlattices-A computational study. Journal of Computational Chemistry 34: 523–532. Available: http://dx.doi.org/10.1002/jcc.23152.en
dc.identifier.issn0192-8651en
dc.identifier.pmid23109263en
dc.identifier.doi10.1002/jcc.23152en
dc.identifier.urihttp://hdl.handle.net/10754/599669en
dc.description.abstractThe preference of experimentally realistic sized 4-nm facetted nanocrystals (NCs), emulating Pb chalcogenide quantum dots, to spontaneously choose a crystal habit for NC superlattices (Face Centered Cubic (FCC) vs. Body Centered Cubic (BCC)) is investigated using molecular simulation approaches. Molecular dynamics simulations, using united atom force fields, are conducted to simulate systems comprised of cube-octahedral-shaped NCs covered by alkyl ligands, in the absence and presence of experimentally used solvents, toluene and hexane. System sizes in the 400,000-500,000-atom scale followed for nanoseconds are required for this computationally intensive study. The key questions addressed here concern the thermodynamic stability of the superlattice and its preference of symmetry, as we vary the ligand length of the chains, from 9 to 24 CH2 groups, and the choice of solvent. We find that hexane and toluene are "good" solvents for the NCs, which penetrate the ligand corona all the way to the NC surfaces. We determine the free energy difference between FCC and BCC NC superlattice symmetries to determine the system's preference for either geometry, as the ratio of the length of the ligand to the diameter of the NC is varied. We explain these preferences in terms of different mechanisms in play, whose relative strength determines the overall choice of geometry. © 2012 Wiley Periodicals, Inc.en
dc.description.sponsorshipContract/grant sponsor: King Abdullah University of Science and Technology (KAUST); contract/grant number: KUS-C1-018-02.en
dc.publisherWiley-Blackwellen
dc.subjectcomputationen
dc.subjectmolecular dynamicsen
dc.subjectnanocrystalsen
dc.subjectsolventen
dc.subjectsuperlattice structureen
dc.titleSolvent-driven symmetry of self-assembled nanocrystal superlattices-A computational studyen
dc.typeArticleen
dc.identifier.journalJournal of Computational Chemistryen
dc.contributor.institutionCornell University, Ithaca, United Statesen
kaust.grant.numberKUS-C1-018-02en

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