A New Mechanism of Stabilization of Large Decahedral Nanoparticles

The stability of decahedral shaped nanoparticles depends upon size. Ino and Marks introduced new mechanisms for the stabilization of decahedra nanoparticles that involves the faceting and formation of surfaces different from {111}. These mechanisms have relevance for small size nanoparticles; however, they do not thoroughly explain how decahedral particles can grow up to 300 nm or more. Here, we report new mechanisms that help stabilize very large decahedra. With the use of aberration-corrected scanning transmission electron microscopy, we observed the formation of high index facets, determined to be of the {511} family, on all five sides of the particles. Surface dislocations strings are also observed. In addition, surface reconstruction of the {001} surfaces can also be observed in two different orientations: with hexagonal strings along the [110] and [410] directions.