Chemical interface damping in single gold nanorods coated with silver via hot electron-mediated photoreduction

Abstract

Herein, we investigated the photoreduction of silver (Ag) ions on gold nanorods coated with mesoporous silica shell (AuNRs@mSiO2) induced by hot electrons generated in Au via localized surface plasmon resonance (LSPR) excitation. In addition, we investigated chemical interface damping (CID) using pyridine as the adsorbate in single Ag-coated AuNRs@mSiO2. The Ag deposition caused a blue shift and linewidth broadening of the LSPR peak of the AuNRs@mSiO2. The subsequent chemisorption of pyridine on Ag-coated AuNRs@mSiO2 resulted in a red shift and additional LSPR linewidth broadening. Finally, we demonstrated real-time time-dependent changes in LSPR peak wavelength and linewidth during the sequential processes of hot electron-mediated Ag deposition and pyridine adsorption on a single AuNR@mSiO2 in a flow cell. Therefore, we provided a deep understanding of hot electron-triggered Ag coating and CID induced by pyridine adsorption in single AuNRs@mSiO2 coated with Ag.