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

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.