Elastic Strain Energy Effects in Faceted Decahedral Nanoparticles

Abstract

Decahedral morphology, with re-entrant surface modifications, is one of the common structures observed in nanoparticles. These motifs, although thermodynamically stable only at very small size ranges, have been experimentally observed to grow up to much larger sizes (100 nm to several micrometers). Whereas the surface energy plays an important role, the contributions of the elastic strain energy are nonnegligible at larger sizes and the effect of stress relaxation due to re-entrant surface faceting is poorly understood. In this article, the volumetric strain energy due to the disclination defect is computed using finite element analysis and the relaxation due to the formation of re-entrant surfaces is shown. Contrary to conventional wisdom, the disclination strain energy is shown to be a nontrivial function of the geometry and in general increases with increasing aspect ratio. The computed strain energies also result in approximately 50% increase in the stability regime than the previously reported results obtained using thermodynamical analysis. Finally, finite element analyses are utilized to explain the commonly observed defect configurations and compute the internal rigid body rotations in these particles.

Determination of the surface morphology of gold-decahedra nanoparticles using an off-axis electron holography dual-lens imaging system

“…6 shows that the nanoparticle has steps, wedges in the corners and complicated rough surface is consistent with a structure produced by the kinetics as recently discussed by (Patala et al, 2013). The steps with kinks correspond to the morphology obtained by growth by step movement, i.e., atoms are added to the steps which provoke their movement, which is a classical mechanism for crystal growth.…”

Advanced Electron Microscopy in the Study of Multimetallic Nanoparticles

“…The model shown in Fig. 3.14b shows that the nanoparticle has steps, wedges in the corners, and complicated rough surface which is consistent with a structure produced by the kinetics, as has been recently discussed by Patala et al [ 76 ]. The steps with kinks correspond to the morphology obtained by growth by step movement, i.e., atoms are added to the steps which provoke their movement; this is a classical mechanism of crystal growth.…”

Defect‐Directed Growth of Symmetrically Branched Metal Nanocrystals

“…The subscript i and t subscripts refer to certain facets and the twin boundary, respectively . Their finite element analysis revealed that a balance between surface energy and volumetric strain energy accounts for different decahedral shapes at different particle sizes . At smaller sizes, of the NC is small, and the free energy is dominated by the surface energy term, favoring convex decahedra.…”