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

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