Ozaki Koichi, Nishiyama Fumitaka, Takahiro Katsumi
Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto 606-8585, Japan.
Research Institute for Nanodevice and Bio Systems, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
Nanomaterials (Basel). 2021 Mar 11;11(3):701. doi: 10.3390/nano11030701.
Fresh Ag nanoparticles (NPs) dispersed on a transparent SiO 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.
分散在透明SiO上的新鲜银纳米颗粒（NPs）在可见光范围内呈现出源于局域表面等离子体共振（LSPR）的强烈光学消光带。当银纳米颗粒在环境空气中储存两周时，LSPR带的强度减弱。与视觉颜色变化相对应的减弱速率和LSPR波长偏移强烈依赖于银纳米颗粒所处的环境。结合成分和形态变化讨论了颜色变化的起源。在一种情况下，在我们实验室中放置在通风扇附近的银纳米颗粒观察到先是变蓝然后迅速褪色，这是由于大量的S和Cl吸附在银纳米颗粒表面以及颗粒粗化所致。这种颜色变化推断出环境中存在大量的S和Cl。在另一种情况下，储存在不锈钢制成的干燥器中的银纳米颗粒观察到LSPR带显著蓝移，这源于CN和/或HCN化合物的形成以及表面粗糙化。它们的颜色从栗色变为微红色，表明干燥器内部存在此类分子。
