Size and shape of nanoclusters: single-shot imaging approach.
Bottom Line: A method of single-shot imaging via aberration-corrected scanning transmission electron microscopy equipped with high angle annular dark-field detector (STEM-HAADF) has been applied to size-selected gold model catalysts (Au(25) and Au(39) ) on hydroxyapatite.Through quantitative intensity analysis, the size, in terms of number of atoms as well as 3D shape of the clusters are obtained.
Affiliation: Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK.Show MeSH
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Mentions: The results in Figure 2 show that a large fraction of the clusters in both samples had aggregated, consisting several clusters of initial sizes. The clear integer multiples in the intensity histograms suggest that the aggregation is not via an Ostwald ripening process, rather it may be through cluster fusion, in which clusters retained their original identities. This is consistent with the broad cluster diameter distribution (full-width-half-maximum) in each case, 1.25 nm for Au25 and 1.5 nm for Au39, with the mean diameter of around 1.7–1.9 nm (See Figure3).
Affiliation: Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK.