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.

Tuning Chemical Interface Damping: Competition between Surface Damping Pathways in Amalgamated Gold Nanorods Coated with Mesoporous Silica Shells

“…In this study, the competition among the surface damping pathways was examined to elucidate the chemical effects. Recently, adsorbates have been reported to provide an additional plasmon damping pathway called CID. ,,,, As shown in Figure A, closely or strongly interacting adsorbates induce the direct generation of hot electrons for the empty lowest unoccupied molecular orbital (LUMO) of the adsorbate within 5 to 100 fs. − Accordingly, the LSPR peak is redshifted and decreases in intensity, and the line width broadens. ,− In this study, thiol chemisorption can result in another CID pathway in addition to the existing surface damping pathway induced by Hg coating on amalgamated AuNRs@ m SiO 2 . Thus, the line width narrowing in Figure can be interpreted in terms of the coexistence and competition between the two surface damping pathways in a single amalgamated AuNRs@ m SiO 2 .…”

“…To the best of our knowledge, no studies have reported on amalgamated AuNRs@ m SiO 2 exposed to adsorbate molecules that may promote changes in the LSPR properties of the single NPs. Furthermore, chemical interface damping (CID), − one of the plasmon decay pathways in plasmonic NPs, and its competition with other surface damping pathways in amalgamated AuNRs@ m SiO 2 remain largely unstudied.…”

Single-Particle Spectroelectrochemistry: Electrochemical Approaches for Tuning Chemical Interfaces and Plasmon Damping in Single Gold Nanorods

“…4−7 Single-particle dark-field (DF) microscopy and spectroscopy studies have successfully revealed that the withdrawal of hot-electron energy by surface thiol molecules at the Au−thiol interface results in the loss of LSPR spectral intensity, redshift, and line width broadening (full width at half-maximum [fwhm]) of the LSPR peak. 6,7,12,14,15,[18][19][20]22 Furthermore, in our recent studies, we demonstrated the tunability of the CID process by regulating the electron-withdrawing and electron-donating properties of thiophenol (TP) adsorbate molecules. 7 We also achieved in situ reversible tuning of CID by manipulating the host−guest supramolecular interactions.…”

“…The strong interaction of adsorbate molecules causes the decay of LSPR at the metal/dielectric interface through the direct excitation of hot-electron energy into the lowest unoccupied molecular orbitals (LUMOs) of the adsorbate molecules, and this phenomenon is called chemical interface damping (CID). ,,,− Thiol (−SH) molecules with sulfur atoms at their tail ends are known to have a strong affinity for Au surfaces, forming a strong covalent soft–soft bonding with the Au surface atoms. − Single-particle dark-field (DF) microscopy and spectroscopy studies have successfully revealed that the withdrawal of hot-electron energy by surface thiol molecules at the Au–thiol interface results in the loss of LSPR spectral intensity, redshift, and line width broadening (full width at half-maximum [fwhm]) of the LSPR peak. ,,,,,− , Furthermore, in our recent studies, we demonstrated the tunability of the CID process by regulating the electron-withdrawing and electron-donating properties of thiophenol (TP) adsorbate molecules . We also achieved in situ reversible tuning of CID by manipulating the host–guest supramolecular interactions. , …”

In situ reversible tuning of chemical interface damping in mesoporous silica-coated gold nanorods via direct adsorption and removal of thiol

“…[14][15][16][17] In recent years, CID has been studied in various types of AuNPs, including gold bipyramids, 17 silver-coated AuNRs, 18,19 and silicacoated AuNRs. 20 In addition, the CID effect induced by various adsorbate molecules, including pyridine, amine (-NH 2 ), and biotinylated proteins, has been recently investigated. 21 Furthermore, the control of CID in AuNRs was achieved by tuning both electron-donating and electron-withdrawing features of adsorbate molecules and by introducing cucurbiturilbased host-guest supramolecular chemistry.…”