Single-particle correlation study: Chemical interface damping in gold nanorods coated with mesoporous silica shell

Abstract

Chemical interface damping (CID) is the most recently suggested plasmon damping pathway induced by adsorbate molecules in gold nanoparticles. Despite recent advances in this field, CID has not been studied in gold nanorods coated with mesoporous silica shells (AuNRs@mSiO2). Herein, we conducted a single-particle correlation study to elucidate CID using p-nitrothiophenol (p-NTP) as adsorbates in single AuNRs@mSiO2. Through surface-enhanced Raman spectroscopy studies, we confirmed that p-NTP with a strong electron-withdrawing group was effectively adsorbed on the AuNR cores. Following the chemisorption of p-NTP, a strong CID was observed with localized surface plasmon resonance (LSPR) linewidth broadening through the preferred interaction between sulfur and the Au surfaces. Furthermore, we presented the molecular binding effect on the LSPR linewidth of single AuNRs@mSiO2 during the reaction with p-NTP in real-time. Thus, the result further supported that the CID could be used to develop LSPR sensors having low sensitivity to the medium dielectric constant.