Modulation of the Interfacial Electronic and Ultrafast Charge Transfer in ZnIn₂S₄/GaSe Heterostructures

Understanding the dynamics mechanism of photogenerated carrier separation and modulation at an interface is crucial for high performance two-dimensional van der Waals (vdW) heterostructure photocatalysts. Here, we report the interfacial electronic and ultrafast carrier dynamics of the ZnIn2S4(ZIS)/GaSe vdW heterostructure under the modulation of the external electric field and biaxial strain using HSE06 hybrid functional theory and ab initio nonadiabatic molecular dynamics. The ZIS/GaSe vdW heterostructure with AB stacking mode exhibits excellent the thermodynamic and mechanical stability, and the hole mobility reaches 10,885 cm2 V–1 s–1 in the x direction. Meanwhile, the recombination time of interfacial electron and hole is 3.782 ps, which is shorter than the transfer time. Therefore, the interfacial charge transfer belongs to the S-scheme mechanism, which can effectively separate the photogenerated carrier and enhance the redox capability for HER, this is due to the bending of the energy band by the internal electric field at the interface. Additionally, we find that the ultrafast interfacial charge transfer dynamics can be further controlled by external electric fields and biaxial strain, namely, it significantly modulates the strength of phonon excitation participating in electron–phonon coupling. In particular, the negative electric field and tensile strain obviously accelerate interfacial charge transfer dynamics, facilitating the separation of electron and hole, the STH efficiency reaches 27.50% under an electric field of −0.3 V/Å. The present work is expected to provide valuable insights on design and modulation of high performance functional photocatalysts.