Tuning Chemical Interface Damping: Interfacial Electronic Effects of Adsorbate Molecules and Sharp Tips of Single Gold Bipyramids

Abstract

The optimization of the localized surface plasmon resonance (LSPR)-decaying channels of hotelectrons is essential for efficient optical and photochemical processes. Understanding and having the ability to control chemical interface damping (CID) channel contributions will bring about new possibilities for tuning the efficiency of plasmonic hot-electron energy transfer in artificial devices. In this scanning electron microscopy-correlated dark-field scattering study, the CID was controlled by focusing on the electronic nature of disubstituted benzene rings acting as adsorbates, as well as the effects of sharp tips on gold bipyramids (AuBPs) with similar aspect ratios to those of gold nanorods. The results showed that the sharp tips on single AuBPs, as well as the electronic effects of the adsorbate molecules, increase the interfacial contact between the nanoparticles and adsorbate molecules. Electron withdrawing groups (EWGs) on the adsorbates induce larger homogeneous LSPR line widths compared to those of electron donating groups (EDGs). Depending on the location (ortho, meta, and para) of the EDG, the effect of benzene rings with an EDG, which was considered to be induced by sulfur atoms bound to the nanoparticle surface, is weakened by the back transfer of electrons facilitated by the difference in the availability of the electrons of the EDG. Therefore, this study reports that the CID in the LSPR total decay channels can be tuned by controlling the electron withdrawing and electron donating features of adsorbate molecules with the surface topology of metal.

Symmetry Breaking in Monometallic Nanocrystals toward Broadband and Direct Electron Transfer Enhanced Plasmonic Photocatalysis

“…Actually, it has been reported that the CID pathway is well tunable by different types of ligands. [ 36 ] To this end, we exchange four types of thiol ligands with similar molecular structures but different substituents on a benzene ring onto the surface of RS‐Au nanocrystals, including 4‐MP with a para OH group, 4‐nitrothiophenol (4‐NTP) with a para NO 2 group, 4‐mercaptobenzoic acid (4‐MBA) with a para COOH group, and 4‐aminothiophenol (4‐ATP) with a para NH 2 group. As shown in Figure S18 in the Supporting Information, the extinction spectra of surface exchanged RS‐Au colloidal solution exhibit different degrees of plasmon peak broadening and red‐shift, which are characterized for the CID effects.…”

“…The corresponding order in CID enhancement coincides well with the literature. [ 36 ] Interestingly, RS‐Au nanocrystals exchanged with these four types of thiol ligands exhibit quite different activity toward the H 2 production, which clearly indicates that ligands play a key role in the hydrolysis of AB molecules. Moreover, the activity exactly follows the order of CID enhancement as 4‐NTP > 4‐MBA > 4‐MP > 4‐ATP, which unambiguously demonstrates that the direct electron transfer mediated by CID pathway dominates the reaction activity.…”

Prospects of Coupled Organic–Inorganic Nanostructures for Charge and Energy Transfer Applications

“…Moreover, experimental evidence shows that CID by adsorbates is able to retard the thermalization process of hot charge carriers (picosecond regime) by the repeated back and forth transfer of hot electrons between the metal and the adsorbates [165] . Some factors need to be taken into account in order to increase efficiency by CID [166] . In contrast to the indirect transfer mechanism, the direct electron transfer requires not only an orbital overlap, but also strong hybridization between the metallic nanoparticle surface and the adsorbate [152] .…”

Perspektiven gekoppelter organisch‐anorganischer Nanostrukturen für Ladungs‐ und Energietransferanwendungen

“…Darüber hinaus zeigen experimentelle Belege, dass die CID durch Adsorbate in der Lage ist, die Thermalisierung der heißen Ladungsträger (Picosekundenbereich)zu verzögern, indem die heißen Elektronen wiederholt zwischen Metall und Adsorbaten hin und her übertragen werden [165] . Um die Effizienz durch CID zu steigern, müssen einige Faktoren berücksichtigt werden [166] . Im Gegensatz zum indirekten Transfermechanismus erfordert der direkte Elektronentransfer nicht nur eine Orbitalüberlappung, sondern auch eine starke Hybridisierung zwischen der Oberfläche der metallischen Nanopartikel und dem Adsorbat [152] .…”