On the nanometer scale, size reduction effects affect materials properties. Au and Ag nanoparticles are interesting cases owing to a structural transition that occurs at nanometric sizes; this has been explored, for example, to change material properties. Here, we present structural studies on dodecanethiol-capped Au and Ag colloidal nanoparticles synthesized at room temperature and 80 °C. For the same synthesis conditions, Au nanoparticle sizes are smaller than Ag ones. From the structure point of view, the synthesis temperature has a minor effect on Au nanoparticles but it induces stacking faults and twin planes in the Ag case. These results suggest that hexagonal close-packed symmetry may be favored for Ag for certain synthesis conditions, but this has not been identified for Au.
- Colloidal gold
- High-resolution transmission electron microscopy
- X-ray diffraction