Plasmon-Exciton Coupling Effect on Plasmon Damping

TL;DR

This study investigates how plasmon-exciton interactions in GNR-2D material hybrids influence plasmon damping, revealing that interfacial effects and charge transfer significantly contribute to plasmon decay, advancing understanding of hybrid plasmonic systems.

Contribution

The paper introduces a single-particle spectroscopy method with in situ nanomanipulation to directly measure plasmon damping and distinguish between charge transfer and energy transfer channels in GNR-2D material hybrids.

Findings

Plasmon-exciton coupling induces plasmon damping in GNR-WSe2 hybrids.

Interfacial contact layers are the main contributors to plasmon damping.

Charge transfer and resonant energy transfer channels can be isolated using hBN layers.

Abstract

Plasmon decay via the surface or interface is a critical process for practical energy conversion and plasmonic catalysis. However, the relationship between plasmon damping and the coupling between the plasmon and 2D materials is still unclear. The spectral splitting due to plasmon-exciton interaction impedes the conventional single-particle method to evaluate the plasmon damping rate by the spectral linewidth directly. Here, we investigated the interaction between a single gold nanorod (GNR) and 2D materials using the single-particle spectroscopy method assisted with in situ nanomanipulation technique by comparing scattering intensity and linewidth together. Our approach allows us to indisputably identify that the plasmon-exciton coupling in the GNR-WSe2 hybrid would induce plasmon damping. We can also isolate the contribution between the charge transfer channel and resonant energy transfer channel for the plasmon decay in the GNR-graphene hybrid by comparing that with thin hBN layers as an intermediate medium to block the charge transfer. We find out that the contact layer between the GNR and 2D materials contributes most of the interfacial plasmon damping. These findings contribute to a deep understanding of interfacial excitonic effects on the plasmon and 2D materials hybrid.