Chemical ordering-driven modulation of plasmonic hot carriers in Janus nanostructures

Abstract

Janus bimetallic nanostructures offer a promising means for achieving directional charge separation in plasmon-enhanced photocatalysis, though the impact of chemical ordering within the metal domain has not been thoroughly examined. In this study, we conduct a comparative theoretical analysis of two exemplary heterostructures: AgAu–CdSe and AuAg–CdSe, utilizing first-principles simulations to elucidate the ultrafast dynamics involved in the generation and transfer of plasmon-induced hot carriers. Our findings indicate that the spatial positioning of Au and Ag strongly influences the plasmon–semiconductor interaction: AuAg–CdSe, characterized by Ag at the interface, displays stronger electronic hybridization, a wider and more energetic hot-carrier distribution, and significantly improved charge injection into the CdSe semiconductor. Conversely, AgAu–CdSe demonstrates more localized plasmonic modes and symmetrical, albeit weaker, interfacial transfer. These findings highlight the critical importance of chemical ordering for optimizing hot-carrier extraction. Our results offer practical design guidelines for engineering plasmonic nanostructures with improved photocatalytic performance through precise interface-level control.