Influence of the Preferred Orientation of Pyridine Derivatives with Donor Substituents on Chemical Interface Damping Induced in Silver-Coated Gold Nanorods with Different Shell Thicknesses

Abstract

Chemical interface damping (CID) is one of the plasmon decay processes caused by adsorbate molecules in gold nanoparticles. Despite the advances in this field, the effect of pyridine derivatives having a preferred orientation on CID in silver-coated gold nanorods (AuNRs@Ag, core@shell) with different shell thicknesses remains unknown. Herein, dark-field scattering studies using pyridine derivatives with donor substituents as adsorbates in single AuNRs@Ag with two different Ag shell thicknesses are described. Pyridine derivatives having electrondonating groups (EDGs) were adsorbed on single AuNRs@Ag and induced a strong CID through the interaction of nitrogen with the Ag surface. AuNRs@Ag with thick shells showed a considerably enhanced CID effect compared with AuNRs@Ag with thin shells for all pyridine derivatives. Furthermore, pyridine derivatives with EDGs in the para position (4-aminopyridine and 4-dimethylaminopyridine) caused a decrease in the localized surface plasmon resonance (LSPR) linewidth broadening of single AuNRs@Ag compared with unsubstituted pyridine under the same experimental conditions. In contrast to the high inclination of pyridine molecules, pyridine derivatives bearing EDGs adopted a parallel orientation to the Ag surface according to surface-enhanced Raman spectroscopy and dynamic light scattering measurements, which resulted in different surface coverage on the Ag surface and decreased LSPR linewidth broadening. Therefore, this study provides deeper understanding of the effects of pyridine derivatives with donor substituents and Ag shell thickness on CID in single AuNRs@Ag.

Fast Surface Restructuring within the Gap of Au Nanocube Dimer for the Enhancement of Catalytic Efficiency

“…Then, dark-field optical microscope (DFM) was used to characterize the scattering feature of these particles at the single-particle level. 9,12,[33][34][35][36][37][38] As shown in Figure 1d, all of the AuCMs disperse separately with uniform and characteristic green color. However, for the AuCDs, noticeable red-shift in the dark-field image can be observed after the dimerization process (Figure 1g).…”

Determining the Preferred Orientation of Silver-Plating via X-ray Diffraction Profile

“…Practically, polycrystalline plating films reveal some degree of preferred orientation owing to the forces evolving crystal growth [ 1 , 2 , 3 ]. For this reason, knowledge of the evolution of preferred orientations can provide valuable information to optimize the preparing process [ 4 , 5 , 6 ].…”

Single-particle study: effects of mercury amalgamation on morphological and spectral changes in anisotropic gold nanorods

“…1A, AuNRs were prepared by drop-casting the AuNR solution on a precleaned glass substrate and then treated with oxygen plasma for 30 s to remove surface CTAB of AuNRs. 14,16,17 A solution containing 10 mM NaBH 4 and 10 µM HgCl 2 was then dropped on the AuNRs deposited on a glass substrate. The Hg concentration can affect the structural changes of AuNRs.…”