Engineering charge transfer and indirect exciton dynamics in 0D/2D heterostructures via hydrostatic pressure

Abstract

This study systematically investigates the charge transfer dynamics in 0D/2D heterostructures composed of CdSe/ZnS quantum dots and WS2 using high-pressure femtosecond pump–probe techniques. Steady-state photoluminescence measurements reveal a significant reversal of the heterostructure's quenching factor at approximately 0.71 GPa. Simultaneously, the charge transfer rate reaches a maximum near this pressure before gradually decreasing with further pressure increase. Transient absorption spectroscopy analysis confirms that this phenomenon originates from indirect excitons formed in the heterostructure under high pressure. These indirect excitons consist of valence band holes from the band nesting of WS2 and conduction band electrons from the quantum dots. The lifetime of these indirect excitons shows a pronounced shortening trend with increasing pressure. This study elucidates the synergistic regulation of charge transfer rates and indirect exciton dynamics in heterostructures by external pressure. This study provides ultrafast spectroscopic measurement and kinetic control of indirect exciton dynamics in 0D/2D heterostructures under high pressure, providing valuable insights and an experimental foundation for studying optoelectronic coupling processes in 0D/2D heterostructures under extreme conditions.