Color Changes in Ag Nanoparticle Aggregates Placed in Various Environments: Their Application to Air Monitoring

Nanomaterials

卷:11

Katsumi Takahiro¹  Koichi Ozaki¹  Fumitaka Nishiyama² 

[1] Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto 606-8585, Japan;

[2] Research Institute for Nanodevice and Bio Systems, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima 739-8527, Japan;

关键词: Ag nanoparticle;    localized surface plasmon resonance;    color;    red-shift;    blue-shift;   

DOI  :  10.3390/nano11030701

来源: DOAJ

【 摘 要 】

Fresh Ag nanoparticles (NPs) dispersed on a transparent SiO₂ exhibit an intense optical extinction band originating in localized surface plasmon resonance (LSPR) in the visible range. The intensity of the LSPR band weakened when the Ag NPs was stored in ambient air for two weeks. The rate of the weakening and the LSPR wavelength shift, corresponding to visual chromatic changes, strongly depended on the environment in which Ag NPs were set. The origin of a chromatic change was discussed along with both compositional and morphological changes. In one case, bluish coloring followed by a prompt discoloring was observed for Ag NPs placed near the ventilation fan in our laboratory, resulted from adsorption of large amounts of S and Cl on Ag NP surfaces as well as particle coarsening. Such color changes deduce the presence of significant amounts of S and Cl in the environment. In another case, a remarkable blue-shift of the LSPR band was observed for the Ag NPs stored in the desiccator made of stainless steel, originated in the formation of CN and/or HCN compounds and surface roughening. Their color changed from maroon to reddish, suggesting that such molecules were present inside the desiccator.

【 授权许可】

Unknown