Atomic Scale Mechanisms Underlying Thermal Reshaping of Anisotropic Gold Nanocrystals Revealed by in Situ Electron Microscopy

Cited 4 time in webofscience Cited 0 time in scopus
  • Hit : 186
  • Download : 0
Understanding the shape transformation processes of anisotropic nanocrystals is an essential step toward fully exploiting their remarkable shape-dependent properties. Here, we employ environmental transmission electron microscopy with controlled heating to directly visualize the thermal reshaping dynamics of gold nanorods and triangular nanoplates at the atomic level. Upon heating above 180 degrees C in 1 mbar of oxygen, thiol ligand molecules that are stabilizing these metastable nanostructures desorb to allow the subsequent migration of surface atoms. As a consequence, nanorods undergo rounding into ellipsoids, with indiscriminate surface migration of vertex atoms to the sides being mediated by the development of multiple high-index facets. By contrast, triangular nanoplates exhibit truncation of their vertices, which proceeds via selective layerby-layer migration of vertex atoms to the triangular faces until a hexagonal shape is attained. Although the thermodynamic driving force is the minimization of the fraction of undercoordinated surface atoms, with the final structure being an isotropic sphere, both surface curvature and surface faceting play a role in determining the pathway to be taken. The peculiar morphology of triangular nanoplates allowed the transition to hexagonal nanoplates to occur with the structure remaining enclosed by stable {111} facets on all faces. Our results demonstrate how in situ electron microscopy can afford fundamental insights into the reshaping mechanisms of anisotropic nanocrystals.
Publisher
AMER CHEMICAL SOC
Issue Date
2020-06
Language
English
Article Type
Article
Citation

JOURNAL OF PHYSICAL CHEMISTRY C, v.124, no.23, pp.12855 - 12863

ISSN
1932-7447
DOI
10.1021/acs.jpcc.0c04281
URI
http://hdl.handle.net/10203/275605
Appears in Collection
CH-Journal Papers(저널논문)
Files in This Item
There are no files associated with this item.
This item is cited by other documents in WoS
⊙ Detail Information in WoSⓡ Click to see webofscience_button
⊙ Cited 4 items in WoS Click to see citing articles in records_button

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0