Including surface ligand effects in continuum elastic models of nanocrystal vibrations
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1705.07468.pdf
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Author(s)
Lee, Elizabeth M.
Mork, Anna Jolene
Willard, Adam P.
Tisdale, William
Date Issued
July 2017
Journal
Journal of Chemical Physics
Publisher
American Institute of Physics (AIP)
Citation
Lee, Elizabeth M. Y. et al. “Including Surface Ligand Effects in Continuum Elastic Models of Nanocrystal Vibrations.” The Journal of Chemical Physics 147, 4 (July 2017): 044711 © 2017 Author(s)
Version
Original manuscript
Abstract
The measured low frequency vibrational energies of some quantum dots (QDs) deviate from the predictions of traditional elastic continuum models. Recent experiments have revealed that these deviations can be tuned by changing the ligands that passivate the QD surface. This observation has led to speculation that these deviations are due to a mass-loading effect of the surface ligands. In this article, we address this speculation by formulating a continuum elastic theory that includes the dynamical loading by elastic surface ligands. We demonstrate that this model is capable of accurately reproducing the l = 0 phonon energy across a variety of different QD samples, including cores with different ligand identities and epitaxially grown CdSe/CdS core/shell heterostructures. We highlight that our model performs well even in the small QD regime, where traditional elastic continuum models are especially prone to failure. Furthermore, we show that our model combined with Raman measurements can be used to infer the elastic properties of surface bound ligands, such as sound velocities and elastic moduli, that are otherwise challenging to measure.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1063/1.4995439
