Design of Multifunctional Optoelectronic Devices in a Si(2)PAs/ZrSSe Heterostructure via Multiphysics Coupling Induced by Dipole Engineering.

Dipole engineering emerges as a foundational strategy for manipulating the dynamics of photoexcited carriers at heterostructure interfaces. Here, using first-principles calculations on a dual-Janus monolayer SiPAs/ZrSSe heterostructure, we demonstrate that controlled interfacial dipole alignment enables the deliberate inversion of band ordering, thereby dictating charge-transfer pathways. In an optimal configuration, this intrinsic field engineering facilitates direct Z-scheme photocatalytic water splitting, which remains functional across a wide pH spectrum. Crucially, the synergistic coupling between the engineered interfacial dipole and the material's intrinsic polar field leads to a pronounced enhancement in both solar-to-hydrogen conversion and photovoltaic efficiencies. Furthermore, we conceptualize a polarized photodetector model where tailored dipole interactions yield a 300% increase in optical responsivity. This work establishes dipole engineering not merely as a material-specific adjustment but as an intrinsic design paradigm for high-performance optoelectronics, offering a powerful alternative to reliance on external stimuli.