Enhanced reactivity and related optical changes of Ag nanoparticles on amorphous Al₂O₃ supports

Autor: R J, Peláez, A, Castelo, C N, Afonso, A, Borrás, J P, Espinós, S, Riedel, P, Leiderer, J, Boneberg
Rok vydání: 2013
Zdroj: Nanotechnology. 24(36)
ISSN: 1361-6528
Popis: Pairs of samples containing Ag nanoparticles (NPs) of different dimensions have been produced under the same conditions but on different substrates, namely standard glass slides and a thin layer of amorphous aluminum oxide (a-Al₂O₃) on-glass. Upon storage in ambient conditions (air and room temperature) the color of samples changed and a blue-shift and damping of the surface plasmon resonance was observed. The changes are weaker for the samples on-glass and tend to saturate after 12 months. In contrast, the changes for the samples on a-Al₂O₃ appear to be still progressing after 25 months. While x-ray photoelectron spectroscopy shows a slight sulfurization and negligible oxidation of the Ag for the on-glass samples upon 25 months aging, it shows that Ag is strongly oxidized for the on a-Al₂O₃ samples and sulfurization is negligible. Both optical and chemical results are consistent with the production of a shell at the expense of a reduction of the metal core dimensions, the latter being responsible for the blue-shift and related to the small (10 nm initial diameter) of the NPs. The enhanced reactivity of the Ag NPs on the a-Al₂O₃ supports goes along with specific morphological changes of the Ag NPs and the observation of nitrogen.
Databáze: OpenAIRE