Thermal Stability and Morphological Transformations of Au<sub>core</sub>−Co<sub>shell</sub> Nanocrucibles

2010-09-09T00:00:00Z (GMT) by Tianlong Wen Kannan M. Krishnan
Au<sub>core</sub>−Co<sub>shell</sub> nanoparticles were synthesized by a wet-chemical method in organic solvent and their thermal stability was studied by annealing experiments over a wide temperature range (200−450 °C). During heating, atoms within the core−shell nanoparticles migrate to transform their initial core−shell morphology to a stable “peanut” structure. We show that this morphological transformation occurs by a well-defined series of energy minimization steps that sequentially reduce the energy due to intraphase grain boundaries within the cobalt shell, the interface energy between the gold core and the cobalt shell, and the overall strain energy.