Modulation of multidimensional interfacial effects in different stacking Bi₂Se₃/WS₂ heterojunctions

Interface engineering in van der Waals heterojunctions is key to optimizing charge dynamics for high-performance optoelectronic and photocatalytic devices. However, the modulation mechanisms of interfacial effects in heterojunctions with different stacking structures remain elusive, which hinders the exploitation and further tailoring of these effects for device applications. This paper systematically investigates the multidimensional modulation of interface engineering in WS₂/Bi₂Se₃ and Bi₂Se₃/WS₂ heterojunctions, highlighting the impact of stacking sequence on interlayer coupling and exciton dynamics. Multidimensional spectroscopic analysis reveals that Bi₂Se₃/WS₂ heterojunction induces stronger interfacial coupling and facilitates interlayer exciton formation, leading to enhanced charge separation and prolonged carrier lifetimes, in contrast to WS₂/Bi₂Se₃. Compared to WS₂, the Bi₂Se₃/WS₂ heterojunction improves photogenerated carrier lifetime by 1800%, providing a new pathway for directional exciton dissociation. The tunable exciton binding energy and charge transfer dynamics are attributed to the distinct roles of interface states. These findings offer mechanistic insights into the design of interface-controlled 2D heterojunctions and provide new strategies for next-generation nanophotonic systems.