Optical Activity of Metal Nanoclusters Deposited on Regular and Doped Oxide Supports from First-Principles Simulations
We report a computational study and analysis of the optical absorption processes of Ag<sub>20</sub> and Au<sub>20</sub> clusters deposited on the magnesium oxide (100) facet, both regular and including point defects. Ag<sub>20</sub> and Au<sub>20</sub>...
Guardado en:
| Autores principales: | , , |
|---|---|
| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
|
| Materias: | |
| Acceso en línea: | https://doaj.org/article/f6c4bd4dd3004ef6a2d1ba666b4afda6 |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| Sumario: | We report a computational study and analysis of the optical absorption processes of Ag<sub>20</sub> and Au<sub>20</sub> clusters deposited on the magnesium oxide (100) facet, both regular and including point defects. Ag<sub>20</sub> and Au<sub>20</sub> are taken as models of metal nanoparticles and their plasmonic response, MgO as a model of a simple oxide support. We consider oxide defects both on the oxygen anion framework (i.e., a neutral oxygen vacancy) and in the magnesium cation framework (i.e., replacing Mg<sup>++</sup> with a transition metal: Cu<sup>++</sup> or Co<sup>++</sup>). We relax the clusters’ geometries via Density-Functional Theory (DFT) and calculate the photo-absorption spectra via Time-Dependent DFT (TDDFT) simulations on the relaxed geometries. We find that the substrate/cluster interaction induces a broadening and a red-shift of the excited states of the clusters, phenomena that are enhanced by the presence of an oxygen vacancy and its localized excitations. The presence of a transition-metal dopant does not qualitatively affect the spectral profile. However, when it lies next to an oxygen vacancy for Ag<sub>20</sub>, it can strongly enhance the component of the cluster excitations perpendicular to the surface, thus favoring charge injection. |
|---|