Jump to main content
Jump to site search


Ligand dynamics control structure, elasticity, and high-pressure behavior of nanoparticle superlattices

Author affiliations

Abstract

Precise engineering of nanoparticle superlattices (NPSLs) for energy applications requires a molecular-level understanding of the physical factors governing their morphology, periodicity, mechanics, and response to external stimuli. Such knowledge, particularly the impact of ligand dynamics on physical behavior of NPSLs, is still in its infancy. Here, we combine coarse-grained molecular dynamics simulations, and small angle X-ray scattering experiments in a diamond anvil cell to demonstrate that coverage density of capping ligands (i.e., number of ligands per unit area of a nanoparticle's surface), strongly influences the structure, elasticity, and high-pressure behavior of NPSLs using face-centered cubic PbS-NPSLs as a representative example. We demonstrate that ligand coverage density dictates (a) the extent of diffusion of ligands over NP surfaces, (b) spatial distribution of the ligands in the interstitial spaces between neighboring NPs, and (c) the fraction of ligands that interdigitate across different nanoparticles. We find that below a critical coverage density (1.8 nm−2 for 7 nm PbS NPs capped with oleic acid), NPSLs collapse to form disordered aggregates via sintering, even under ambient conditions. Above the threshold ligand coverage density, NPSLs surprisingly preserve their crystalline order even under high applied pressures (∼40–55 GPa), and show a completely reversible pressure behavior. This opens the possibility of reversibly manipulating lattice spacing of NPSLs, and in turn, finely tuning their collective electronic, optical, thermo-mechanical, and magnetic properties.

Graphical abstract: Ligand dynamics control structure, elasticity, and high-pressure behavior of nanoparticle superlattices

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 Dec 2018, accepted on 19 Feb 2019 and first published on 01 Mar 2019


Article type: Paper
DOI: 10.1039/C8NR09699F
Citation: Nanoscale, 2019, Advance Article

  •   Request permissions

    Ligand dynamics control structure, elasticity, and high-pressure behavior of nanoparticle superlattices

    T. K. Patra, H. Chan, P. Podsiadlo, E. V. Shevchenko, S. K. R. S. Sankaranarayanan and B. Narayanan, Nanoscale, 2019, Advance Article , DOI: 10.1039/C8NR09699F

Search articles by author

Spotlight

Advertisements