Interface Engineering\nfor Efficient Photocarrier Generation\nand Transfer in Strongly Coupled Metallic/Semiconducting 1T′/2H\nMoS<sub>2</sub> Heterobilayers

Developing alternative two-dimensional (2D) metallic/semiconducting\n(M/S) van der Waals heterostructures (vdWHs) along with an understanding\nof interfacial photocarrier behavior is crucial for designing high-performance\noptoelectronic devices. Here, we comprehensively explored the photophysical\nmodel of photocarrier generation and interfacial transfer in as-grown\n2D 1T′/2H MoS<sub>2</sub> vdWHs using various spectroscopic\ncharacterizations. We demonstrated the transitions of activated photocarrier\ntransfer trajectories by tuning the pump photon energies across the\n2H MoS<sub>2</sub> bandgap. The importance of confined bilayer transfer\nsystems and strong interlayer coupling at vdW interfaces for transfer\nefficiency was elucidated. Additionally, the fluorophlogopite substrate\nwas found to be an external method for regulating photocarrier generation\nin individual 2H layers through the p-doping effect at the substrate–2H\nlayer interfaces, and this influence was alleviated after introducing\nthe 2H–1T′ vdW interface. Particularly, 1T′ MoS<sub>2</sub> as a broadband hot carrier absorber enabled the ultrafast\n(∼133 fs) injection and extraction of energetic hot carriers\ninto the 2H layer via a photothermionic emission mechanism, achieving\na high efficiency of ∼41% under 900 nm photoexcitation at room\ntemperature. Our work offers fundamental insights into the complex\ninterfacial carrier photophysics in 2D M/S vdWHs, providing a way\nof constructing advanced multifunctional devices by using these emerging\nmaterials as active components and interface engineering.