Thickness Dependent Ultrafast Charge Transfer in BP/MoS₂ Heterostructure

Abstract Constructing high‐performance‐2D heterostructures and deciphering the underlying microscopic mechanism of carrier dynamics are crucial in optoelectronic and photovoltaic applications. Here, taking black phosphorus (BP)/MoS₂ heterostructure with type‐II band alignment as a prototypical example, the ab initio nonadiabatic molecular dynamics simulations demonstrate that the interlayer carrier dynamics are thickness dependent. Specifically, the electron transfer from a monolayer (1L)‐BP to MoS₂ occurs quickly within 54 fs. In contrast, hole transfer can only be observed within 1 ps with BP's layer number N ≥ 2, triggered by the excitation of low‐frequency acoustic phonon and interlayer shear and breathing phonon modes within 100 cm^–1 that enhances the interlayer coupling. Particularly, the electron and hole transfer time exhibits respectively linear and exponential dependence on the layer number N of BP component. The present findings shed new light on improving the process of ultrafast carrier dynamics of 2D heterostructures for photoconversion.