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Abstract
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This paper presents the structuraland spectral variations of individual mesoporous silica-coated gold nanorods(AuNRs@mSiO2)compared to bare AuNRsupon Hg?Au amalgamation. First, the aspect ratio of AuNRs@mSiO2 exposedto Hg solutions was unchanged because the deformation related to the cores of AuNRwas suppressed by the silica shell. Second, dark-field microscopy andspectroscopy revealed a blue shift of the localized surface plasmonresonance (LSPR) wavelength peak and strong plasmondamping in the individual AuNRs@mSiO2 scatteringspectra, exposed to Hg solutions. Furthermore, we investigated time-dependentadsorption kinetics and spectral changes during the formation of Au?Hg amalgamin single AuNRs@mSiO2 overa long time frame without any disturbance from the structural deformation. Theinward Hg diffusion into the AuNRcore caused a gradual red shift and line width narrowing of the LSPR peakwhen AuNRs@mSiO2 werewithdrawn from Hg solution. Thus, this paper provides new insights into therelationship among amalgamation process, morphological change, the role ofsilica shell, Hg inward diffusion, LSPR peak, and line width at thesingle-particle level. |
