Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

Fan, Z. (TU Delft Engineering Thermodynamics)
Lin, L. (TU Delft Engineering Thermodynamics)
Buijs, W. (TU Delft Engineering Thermodynamics)
Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)
van Huis, MA

2016

Cation exchange is a powerful tool for the synthesis of nanostructures such as core–shell nanocrystals, however, the underlying mechanism is poorly understood. Interactions of cations with ligands and solvent molecules are systematically ignored in simulations. Here, we introduce the concept of pseudoligands to incorporate cation-ligand-solvent interactions in molecular dynamics. This leads to excellent agreement with experimental data on cation
exchange of PbS nanocrystals, whereby Pb ions are partially replaced by Cd ions from solution. The temperature and the ligand-type control the exchange rate and equilibrium composition of cations in the nanocrystal. Our simulations reveal that Pb ions are kicked out by exchanged Cd interstitials and migrate through interstitial sites, aided by local relaxations at core–shell interfaces and point defects. We also predict that high-pressure conditions facilitate strongly enhanced cation exchange reactions at elevated temperatures. Our approach is easily extendable to other semiconductor compounds and to other families of
nanocrystals.

chemical sciences
physical chemistry
nanotechnology

http://resolver.tudelft.nl/uuid:de954ea2-905b-4e24-8040-e60088af6eba

https://doi.org/10.1038/ncomms11503

2041-1723

Nature Communications, 7, 1-8

Institutional Repository

journal article

© 2016 Z. Fan, L. Lin, W. Buijs, T.J.H. Vlugt, MA van Huis