Ultrafast Charge Transfer in Perovskite Nanowire/2D Transition Metal Dichalcogenide Heterostructures

Mixed-dimensional van der Waals (vdW) heterostructures between one-dimensional (1D) perovskite nanowires and two-dimensional (2D) transition metal dichalcogenides (TMDCs) hold great potential for novel optoelectronics and light-harvesting applications. However, the ultrafast carrier dynamics between the 1D perovskite nanowires and 2D TMDCs are currently not well understood, which is critical for related optoelectronic applications. Here we demonstrate vdW heterostructures of CsPbBr₃ nanowire/monolayer MoS₂ and CsPbBr₃ nanowire/monolayer WSe₂ and further present systematic investigations on their charge transfer dynamics. We show that CsPbBr₃/MoS₂ and CsPbBr₃/WSe₂ are type-I and type-II heterostructures, respectively. Both electrons and holes transfer from CsPbBr₃ to MoS₂ with an efficiency of 71%. As a contrast, holes transfer from CsPbBr₃ to WSe₂ with a carrier transfer efficiency of 70% and electrons transfer inversely within 7 ps. The ultrafast and efficient charge transfer in the 1D/2D perovskite-TMDC heterostructures suggest great promise in light emission, photodetector, and photovoltaic devices.