Misfit dislocations in multimetallic core-shelled nanoparticles

Core-shelled multimetallic nanoparticles have unique catalytic properties compared to their single-element counterparts. Due to the different lattice parameters of the core and shell, the strain field is built up at the interface between the two phases. As for thin films, a formation of misfit and threading dislocations is an approach to release interface strain. However, for two-phase nanoparticles especially when their sizes are at nanometer scale, their dislocation formation in the volume remains to be investigated owing to the large surface-to-volume ratio. Here, we confirmed the existence of dislocations in the Au-FePt core-shelled nanoparticles of sizes less than 10 nm. It is suggested that the different atom sizes of the core and the shell materials are likely to be a key factor to generate and lock dislocations inside the nanoparticles.