Directory
Dr. MariaLore Sulpizi
| When |
Jul 04, 2016 à 03:00 PM |
|---|---|
| Where |
Grande salle cbp LR6 |
| Contact |
Ivan Rivalta |
From nanoseeds to rods: the microscopic origin of the anisotropic growth
Directly manipulating and controlling the size and shape of metal nanoparticles is a key step for their tailored applications. We use molecular dynamics simulations in order to understand the microscopic origin of the asymmetric growth mechanism in gold nanorods. The different factors influencing the growth are selectively included in the models in order to unravel the role of the the surfactants and ions. In the early stage of the growth, when the seed is only a few nanometers large, a dramatic symmetry breaking occurs. The surfactant layer is preferentially covering the (100) and (110) facets leaving the (111) facets unprotected. Such anisotropdic surfactant layer would, in turn, promote an anisotropic growth where the less protected tips would grow faster.
When silver salt is added to the growing solution the asymmetry between facets is preserved, however the Br- concentration at the interface increases, resulting into an increased surface passivation.