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Published on: September 13, 2020
The possibility and implications of dynamic nanoparticle surfaces
James R McBride1, Timothy J Pennycook, Stephen J Pennycook
1Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, and The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
Semiconductor nanocrystal surfaces are not static but dynamically fluctuate under excitation, creating transient states. This fluxionality challenges existing theories and impacts nanoparticle technology applications.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Surface and interface properties are critical for optimizing material function, especially in semiconductor nanocrystals.
- Existing theories propose static, undefined trap states on nanocrystal surfaces due to incomplete passivation.
- Surface states significantly influence optical properties like fluorescence efficiency, lifetime, and intermittency.
Purpose of the Study:
- To challenge the conventional understanding of static nanocrystal surfaces.
- To introduce and discuss the concept of surface fluxionality in semiconductor nanocrystals.
- To explore the implications of dynamic surface states on nanoparticle optical properties and technology.
Main Methods:
- Acquisition of scanning transmission electron microscope (STEM) movies.
- Development and application of supporting theoretical evidence.
- Analysis of optical properties in the context of dynamic surface behavior.
Main Results:
- Experimental evidence (STEM movies) suggests dynamic fluctuations of the nanocrystal surface under excitation.
- Theoretical support indicates the creation of a dynamic population of surface and subsurface states.
- This fluxionality implies a departure from the traditional model of static trap states.
Conclusions:
- The surface of semiconductor nanocrystals is not static but exhibits fluxional behavior under optical excitation.
- This dynamic nature challenges fundamental understanding of nanoparticle surfaces and their associated trap states.
- Understanding surface fluxionality is crucial for advancing nanoparticle-based technologies and applications.
