Real‐Space Observation of Prolate Monolayer‐Protected Au₃₈ Clusters Using Aberration‐Corrected Scanning Transmission Electron Microscopy

Abstract

The shape of monolayer-protected Au38 clusters on the sub-nanometer scale is obtained by spherical aberration-­corrected scanning transmission electron microscopy under optimized experimental imaging conditions. The cluster shape is generally retained between frames, and statistical analysis of the shape population identifies a high proportion of prolate clusters, consistent with published theoretical calculations and X-ray diffraction results. This method has the potential to characterize other small, ligand-protected nanoparticles as well as clusters or nanoparticles generated by physical methods, such as catalyst particles.