Single-Particle\nSpectroelectrochemistry: Revealing\nthe Electrochemical Tuning Mechanism of Chemical Interface Damping\nin 1,2-Benzenedithiol-Adsorbed Single Gold Nanorods

Chemical interface damping (CID) is a newly proposed\nplasmon damping\npathway based on interfacial hot-electron transfer from metal to adsorbate\nmolecules. However, achieving <i>in situ</i> tunability\nof CID in single gold nanorods (AuNRs) remains a considerable challenge.\nHere, we present the CID effect induced by benzene 1,2-dithiol (BDT)\nmolecule adsorption on single AuNRs and the effective electrochemical\ntunability of CID in BDT-adsorbed AuNRs immobilized on an indium tin\noxide (ITO) surface. Manipulations of the electrochemical potential\nalter the electron density of AuNRs, thereby influencing and tuning\nthe localized surface plasmon resonance (LSPR) spectrum, with cathodic\npotential blueshifting and anodic potential redshifting. The strong\nadsorption of BDT on Au induced CID in single AuNRs. The potential-induced\nLSPR scattering spectra of BDT-adsorbed AuNRs for linear potential\nsweep showed a stable LSPR spectral response, irrespective of the\nconcentrations of BDT molecules. Due to the involvement of two Au–S\nbonds, BDT molecules have a higher free adsorption energy and a lower\ndesorption rate on the Au surface. This resulted in a stable LSPR\nspectral response for a linear electrochemical potential sweep. Furthermore,\na constant anodic and cathodic potential application showed the tunability\nof the CID at the BDT-Au interface.