Plasmon-Mediated Electron Injection from Au Nanorods into MoS2: Traditional versus Photoexcitation Mechanism

Abstract

Summary Using nonadiabatic molecular dynamics simulations combined with time-domain density functional theory, we show that electron injection from gold nanorods into MoS 2 by the traditional mechanism is still faster than energy relaxation causing charge recombination. Plasmon-like excitations decay into free-electron states within 30 fs after photoexcitation of gold nanorods. Electron transfer follows within less than 100 fs, whereas energy relaxation requires 200 fs. Surface plasmons couple to low-frequency phonons of gold, and free charges also couple to higher-frequency phonons of gold and MoS 2 . The contribution of the charge-transfer photoexcitation mechanism to plasmon-driven charge separation depends strongly on the type of donor-acceptor interaction, e.g., chemical versus van der Waals, and more weakly on contact area and system geometry. The simulation generates a detailed time-domain atomistic description of the interfacial plasmon-driven charge separation and relaxation that are fundamental to many applications.