Single-Particle Spectroelectrochemistry: Revealing the Electrochemical Tuning Mechanism of Chemical Interface Damping in 1,2-Benzenedithiol-Adsorbed Single Gold Nanorods.

Chemical interface damping (CID) is a newly proposed plasmon damping pathway based on interfacial hot-electron transfer from metal to adsorbate molecules. However, achieving in situ tunability of CID in single gold nanorods (AuNRs) remains a considerable challenge. Here, we present the CID effect induced by benzene 1,2-dithiol (BDT) molecule adsorption on single AuNRs and the effective electrochemical tunability of CID in BDT-adsorbed AuNRs immobilized on an indium tin oxide (ITO) surface. Manipulations of the electrochemical potential alter the electron density of AuNRs, thereby influencing and tuning the localized surface plasmon resonance (LSPR) spectrum, with cathodic potential blueshifting and anodic potential redshifting. The strong adsorption of BDT on Au induced CID in single AuNRs. The potential-induced LSPR scattering spectra of BDT-adsorbed AuNRs for linear potential sweep showed a stable LSPR spectral response, irrespective of the concentrations of BDT molecules. Due to the involvement of two Au-S bonds, BDT molecules have a higher free adsorption energy and a lower desorption rate on the Au surface. This resulted in a stable LSPR spectral response for a linear electrochemical potential sweep. Furthermore, a constant anodic and cathodic potential application showed the tunability of the CID at the BDT-Au interface.