A fundamental understanding of ultrafast charge transfer dynamics is essential for the rational design of functional optoelectronic and photovoltaic devices. However, the underlying microscopic mechanisms of the charge transfer process at the heterojunction interface remain unclear, particularly regarding the specific role of the interfacial dipole moment and external electric field (EEF). Here, we systematically investigate the ultrafast interfacial charge transfer of $\mathrm{Hf}{\mathrm{S}}_2$/$\mathrm{Mo}X\mathrm{Se}$ ($X=\mathrm{S}$, Se) heterostructures using ab initio nonadiabatic molecular dynamics. The results demonstrate that the $\mathrm{Hf}{\mathrm{S}}_2/{\mathrm{MoSe}}_2$ heterostructure exhibits strong nonadiabatic coupling, and ultrafast interlayer hole and electron transfer occurring within 116 and 136 fs, respectively. Notably, the hole transfer dynamics are significantly suppressed in the symmetry-broken $\mathrm{Hf}{\mathrm{S}}_2$/MoSSe heterostructure, which is primarily attributed to the interfacial dipole substantially modifying both the charge distribution and interlayer coupling strength. Furthermore, within the $\mathrm{Hf}{\mathrm{S}}_2/{\mathrm{MoSe}}_2$ system, we elucidated the asymmetric modulation mechanism of EEFs on interlayer charge transfer dynamics: a negative EEF significantly slows down charge transfer, while a positive EEF accelerates electron transfer but suppresses hole transfer. The elucidation of this specific mechanism provides important theoretical insights for developing high-performance optoelectronic devices based on two-dimensional transition metal dichalcogenide heterostructures.

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• Charge dynamics
• Electric polarization
• Electrical properties
• Electronic structure
• 2-dimensional systems
• Interfaces
• Transition metal dichalcogenides
• Density functional theory
• Molecular dynamics