Investigation of surface reactions on nanoparticle surfaces using liquid cell transmission electron microscopy (LCTEM)

Liquid cell transmission electron microscopy to study surface reactions of nanoparticles, schematic illustration of a liquid cell and representation of the proposed mechanism for particle etching of PbSe by organic transient based on pulse radiolysis and liquid cell transmission electron microscopy studies.

Result of an etching study of PbSe nanoparticles using different fluences (200 and 400) e-∙Å-2∙s-1.

The precise understanding and control of the morphology of nanoparticle surfaces on the nanoscale is one of the basic requirements for the realization of many modern applications, for example in data storage and photonics. Liquid cell transmission electron microscopy (LCTEM) is a promising method that can be used to directly visualize a variety of nanoscale transformations. This enables the precise synthesis of nanostructures with the desired functions.

Scientists from the Hertz electron beam laboratory at the IOM, in cooperation with research teams from the University of Berkeley and the University of Chicago, investigated electron beam-based etching processes on nanoparticles at the atomic level and with a temporal resolution in the nanosecond range. For this purpose, transmission electron microscopy (TEM) was tested on graphene liquid cells in combination with the ultra-fast pulse radiolysis technique. Etching of gold and semiconductor nanocrystals was used as a model system to study and understand the reactivity of the liquid cell solution and its impact on the observed transformations. The etching trajectories of gold nanocrystals in different iron halide solutions showed relevant influencing factors for controlling the etching behavior. In addition, it could be observed that unexpected reactants such as highly oxidized short-lived transient species and organic compounds can have a strong influence on the etching behavior.
Studies on prototypical semiconductor nanomaterials with well-defined crystalline facets also showed how nanoscale shape changes of semiconductors are determined by the reactivity of certain facets in liquid environments.

The results of the studies were published in the Journal of the American Chemical Society (JACS) and in Science Advances:

Publications

M. F. Crook, C. Laube, I. A. Moreno-Hernandez, A. Kahnt, S. Zahn, J. C. Ondry, A. Liu, A. P. Alivisatos
Elucidating the Role of Halides and Iron during Radiolysis-Driven Oxidative Etching of Gold Nanocrystals Using Liquid Cell Transmission Electron Microscopy and Pulse Radiolysis
Journal of the American Chemical Society2021, 143, 11703-11713
https://doi.org/10.1021/jacs.1c05099

C. Yan, D. Byrne, J. C. Ondry, A. Kahnt, I. A. Moreno-Hernandez, G. A. Kamat, Z.-J. Liu, C. Laube, M. F. Crook, Y. Zhang, P. Ercius, A. P. Alivisatos
Facet-selective etching trajectories of individual semiconductor nanocrystals
Science Advances2022, 8, eabq1700
DOI: 10.1126/sciadv.abq1700

 

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