The optimization of the localized surface plasmon resonance (LSPR)-decaying channels of hotelectrons is essential for efficient optical and photochemical processes. Understanding and having the ability to control chemical interface damping (CID) channel contributions will bring about new possibilities for tuning the efficiency of plasmonic hot-electron energy transfer in artificial devices. In this scanning electron microscopy-correlated dark-field scattering study, the CID was controlled by focusing on the electronic nature of disubstituted benzene rings acting as adsorbates, as well as the effects of sharp tips on gold bipyramids (AuBPs) with similar aspect ratios to those of gold nanorods. The results showed that the sharp tips on single AuBPs, as well as the electronic effects of the adsorbate molecules, increase the interfacial contact between the nanoparticles and adsorbate molecules. Electron withdrawing groups (EWGs) on the adsorbates induce larger homogeneous LSPR line widths compared to those of electron donating groups (EDGs). Depending on the location (ortho, meta, and para) of the EDG, the effect of benzene rings with an EDG, which was considered to be induced by sulfur atoms bound to the nanoparticle surface, is weakened by the back transfer of electrons facilitated by the difference in the availability of the electrons of the EDG. Therefore, this study reports that the CID in the LSPR total decay channels can be tuned by controlling the electron withdrawing and electron donating features of adsorbate molecules with the surface topology of metal.

This paper presents the structural and spectral variations of individual mesoporous silica-coated gold nanorods (AuNRs@mSiO 2 ) compared to bare AuNRs upon Hg−Au amalgamation. First, the aspect ratio of AuNRs@mSiO 2 exposed to Hg solutions was unchanged because the deformation related to the cores of AuNR was suppressed by the silica shell. Second, dark-field microscopy and spectroscopy revealed a blue shift of the localized surface plasmon resonance (LSPR) wavelength peak and strong plasmon damping in the individual AuNRs@mSiO 2 scattering spectra, exposed to Hg solutions. Furthermore, we investigated time-dependent adsorption kinetics and spectral changes during the formation of Au−Hg amalgam in single AuNRs@mSiO 2 over a long time frame without any disturbance from the structural deformation. The inward Hg diffusion into the AuNR core caused a gradual red shift and line width narrowing of the LSPR peak when AuNRs@mSiO 2 were withdrawn from Hg solution. Thus, this paper provides new insights into the relationship among amalgamation process, morphological change, the role of silica shell, Hg inward diffusion, LSPR peak, and line width at the single-particle level.

Chemical interface damping in plasmonic gold nanoparticles is closely connected with chemical enhancement in resonance SERS.

This study investigated the amalgamation of gold nanorods (AuNRs) exposed to Hg(II) solution and its effects on structural and spectral changes in single AuNRs using scanning electron microscopy and total...

Increasing the oxygen plasma treatment time gradually broadened the LSPR linewidth of the single gold nanorods.