Ag Dewetting in Cu@Ag Monodisperse Core−Shell Nanoparticles


Anya Muzikansky, Pilkhaz Nanikashvili, Judith Grinblat, and David Zitoun

J. Phys. Chem. C 2013, 117, 3093−3100

Link to the article

We report on the synthesis of monodisperse Cu
and Cu@Ag nanocrystals. Using the same synthetic procedure
in three different temperature ranges, Cu@Ag show very
different stability pathways which we interpret as three
different growth mechanisms: galvanic displacement at low
temperature, metal assisted growth, and overgrowth of Ag at
high temperature. At middle range temperature, Ag shell is
shown to be stable over several months and efficiently
passivates the Cu core. In the two other cases, combined
dynamic light scattering (DLS) and high-resolution transmission
electron microscopy (HRTEM) demonstrate the
diffusion processes of Ag taking place at the surface of Cu
and the dewetting of Ag shell from the surface of Cu to form spherical Ag nanocrystals. This result is a nice example of aging of core/shell nanostructure, and the chemical rearrangement is put in perspective of previously reported theoretical calculations and applications to printed electronics.