Journal article
Annealing-induced reversible change in optical absorption of Ag nanoparticles



Publication Details
Authors:
Bi, H.; Cai, W.; Zhang, L.; Martin, D.; Träger, F.
Publisher:
AIP Publishing
Publication year:
2002
Journal:
Applied Physics Letters
Pages range:
5222-5224
Journal acronym:
Appl. Phys. Lett.
Volume number:
81
Start page:
5222
End page:
5224
ISSN:
0003-6951

Abstract
Optical absorption of silver nanoparticles dispersed within pores of monolithic mesoporous silica was investigated after annealing in different atmospheres. It has been found that treatment in H-2 or N-2 induces a strong surface plasmon resonance (SPR) as usually expected, but air annealing results in the disappearance of the SPR, which is contrary to the fact that bulk metal silver is stable and not oxidized in air at above 200degreesC. The absence and appearance of the SPR absorption can be controlled through alternate annealing in air and H-2 (or N-2). Thermodynamic analysis for oxidation of Ag nanoparticles, by additionally considering the surface and curvature effects of a particle, shows the existence of critical particle size. Only when a Ag particle size is smaller than the critical value is the oxidation possible in air at above 200degreesC. The optical changes are attributed to,the occurrence of the redox of the Ag particles in different atmospheres at a high temperature. (C) 2002 American Institute of Physics. [DOI: 10.1063/1.1532757].


Authors/Editors

Last updated on 2019-01-11 at 16:05