Transition-metal dichalcogenide (TMD) semiconductors have attracted interest as photoelectrochemical (PEC) electrodes due to their novel band-gap structures, optoelectronic properties, and photocatalytic activities. However, the photo-harvesting efficiency still requires improvement. In this study, A TMD stacked heterojunction structure was adopted to further enhance the performance of the PEC cathode. A P-type WSe₂ and an N-type MoS₂ monolayer were stacked layer-by-layer to build a ultrathin vertical heterojunction using a micro-fabrication method. In situ measurement was employed to characterize the intrinsic PEC performance on a single-sheet heterostructure. Benefitting from its built-in electric field and type II band alignment, the MoS₂/WSe₂ bilayer heterojunction exhibited exceptional photocatalytic activity and a high incident photo-to-current conversion efficiency (IPCE). Comparing with the monolayer WSe₂ cathode, the PEC current and the IPCE of the bilayer heterojunction increased by a factor of 5.6 and enhanced 50%, respectively. The intriguing performance renders the MoS₂/WSe₂ heterojunction attractive for application in high-performance PEC water splitting.

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过渡金属二硫化氢（TMD）半导体因其新颖的带隙结构，光电性能和光催化活性而引起人们的关注，成为光电化学（PEC）电极。但是，光收集效率仍然需要改进。在这项研究中，采用了TMD堆叠异质结结构，以进一步增强PEC阴极的性能。甲P型WSE ₂和Ñ型的MoS ₂使用微制造方法将单层一层一层地堆叠起来，以构建超薄的垂直异质结。原位测量用于表征单层异质结构上的固有PEC性能。受益于其内置的电场和II型能带对准，MoS ₂ / WSe ₂双层异质结表现出出色的光催化活性和高入射光电流转换效率（IPCE）。与单层WSe ₂阴极相比，双层异质结的PEC电流和IPCE分别增加了5.6倍和50％。引人入胜的性能使MoS ₂ / WSe ₂ 异质结在高性能PEC水分解中的应用很有吸引力。

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