Publication Date

6-15-2018

Department

Ames Laboratory; Materials Science and Engineering; Physics and Astronomy

Campus Units

Ames Laboratory, Materials Science and Engineering, Physics and Astronomy

OSTI ID+

1483412

Report Number

IS-J 9694

DOI

10.1021/jacs.8b03895

Journal Title

Journal of the American Chemical Society

Volume Number

140

Issue Number

26

First Page

8236

Last Page

8245

Abstract

We elucidate how nanocrystals “bond” to form ordered structures. For that purpose we consider nanocrystal configurations consisting of regular polygons and polyhedra, which are the motifs that constitute single component and binary nanocrystal superlattices, and simulate them using united atom models. We compute the free energy and quantify many body effects, i.e., those that cannot be accounted for by pair potential (two-body) interactions, further showing that they arise from coalescing vortices of capping ligands. We find that such vortex textures exist for configurations with local coordination number ≤6. For higher coordination numbers, vortices are expelled and nanocrystals arrange in configurations with tetrahedral or icosahedral order. We provide explicit formulas for the optimal separations between nanocrystals, which correspond to the minima of the free energies. Our results quantitatively explain the structure of superlattice nanocrystals as reported in experiments and reveal how packing arguments, extended to include soft components, predict ordered nanocrystal aggregation.

DOE Contract Number(s)

AC02-07CH11358

Language

en

Department of Energy Subject Categories

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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