Real-Time TEM and Kinetic Monte Carlo Studies of the Coalescence of Decahedral Gold Nanoparticles

Abstract

We report on a real-time in situ TEM study of the coalescence of individual pairs of decahedral gold nanoparticles, which have been synthesized in solution. We observe the rate of growth of the neck that joins two particles during coalescence and compare this to classical continuum theory and to atomistic kinetic Monte Carlo simulations. We find good agreement between the observations and the simulations but not with the classical continuum model. This disagreement is attributed to the faceted nature of the particles.

Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters

“…Nanoscale dynamics of crystalline clusters, [1][2][3][4] epitaxial structures, [5][6][7] and even liquid jets 8 can differ qualitatively from mesoscale or macroscale behavior described by continuum formalisms. This applies for reshaping of 3D crystalline nanoclusters [1][2][3] and 2D epitaxial nanoclusters.…”

“…This applies for reshaping of 3D crystalline nanoclusters [1][2][3] and 2D epitaxial nanoclusters. 6 Differences occur when linear nanocluster sizes, L, decrease below various characteristic lengths.…”

“…6 Differences occur when linear nanocluster sizes, L, decrease below various characteristic lengths. [1][2][3][9][10][11][12] For L < L k , the characteristic separation between kinks on close-packed step edges, 2D clusters become effectively faceted and reshaping is controlled by inhibited nucleation of new edges. 9 Similar anomalies have been discussed for 3D nanoclusters, but here facets can be macroscopic and nucleation of new layers becomes prohibitive above nanoscale.…”

“…10,14,15 In general, key exponents describing both temporal scaling and size-scaling of relaxation times differ from macroscale theory. [1][2][3]5,6 Note also that reshaping of 2D epitaxial clusters and pits, or 3D clusters and voids in bulk crystals, is equivalent on the macroscale, 16 but not on the nanoscale. 11,12 The size-dependence of diffusivity of supported metal nanoclusters was also found to deviate from macroscale predictions.…”

In Situ Transmission Electron Microscopy of Cadmium Selenide Nanorod Sublimation

“…(23) A dilute solution of nanorods dispersed in toluene was drop-casted onto a commercially available, low thermal drift TEM grid and, sublimation of these nanostructures was recorded. The temperature ramp rate for these grid was 10 6 °C/s, permitting virtually isothermal heating conditions. Videos of CdSe nanorod sublimation at 370, 390, 420, and 450 °C can be found in Videos S1-S4, and selected frames can be found in Figure S1 in the Supporting Information (SI).…”