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)
