Exciton-Plasmon Driven Hot Carriers' Extraction in Cu_2-xS/WS₂ Heterostructure

Hot charge carrier extraction serves as a promising strategy for enhancing the performance of light-driven optoelectronic devices. The integration of plasmonic materials with two-dimensional transition metal chalcogenides (TMCs) may facilitate the simultaneous utilization of plasmon-generated hot charge carriers and high-energy excitons created in TMCs. In the present study, a semiconductor plasmonic-2D heterostructure Cu_2-xS/WS₂, is synthesized to synergistically harness both plasmon-generated hot charge carriers from Cu_2-xS and high-energy excitons from WS₂. Ultrafast transient absorption studies performed under 840 nm photoexcitation confirm the efficient transfer of plasmon-generated hot holes from Cu_2-xS to WS₂. Simultaneously, under nonresonant excitation, hot electrons from the C and D excitonic states of WS₂ are transferred to the conduction band of Cu_2-xS. These findings highlight the potential of semiconducting plasmonic-2D heterostructures for efficient utilization of high energy excitons and localized surface plasmon resonance (LSPR)-generated hot charge carriers, paving the way for advancements in hot carrier-based optoelectronic devices.