Two-dimensional Janus van der Waals (vdW) heterojunctions, referring to the junction containing at least one Janus material, are found to exhibit tuneable electronic structures, wide light adsorption spectra, controllable contact resistance, and sufficient redox potential due to the intrinsic polarization and unique interlayer coupling. These novel structures and properties are promising for the potential applications in electronics and energy conversion devices. To provide a comprehensive picture about the research progress and guide the following investigations, here we summarize their fundamental properties of different types of two-dimensional Janus vdW heterostructures including electronic structure, interface contact and optical properties, and discuss the potential applications in electronics and energy conversion devices. The further challenges and possible research directions of the novel heterojunctions are discussed at the end of this review.

二维Janus van der Waals（vdW）异质结，指的是包含至少一种Janus材料的结，由于其固有的极化和极化作用，具有可调节的电子结构，宽的光吸收光谱，可控的接触电阻以及足够的氧化还原电势。独特的层间耦合。这些新颖的结构和特性有望在电子和能量转换设备中得到潜在的应用。为了提供有关研究进展的全面情况并指导以下研究，在这里我们总结了不同类型的二维Janus vdW异质结构的基本性质，包括电子结构，界面接触和光学性质，并讨论了在电子和能源中的潜在应用转换设备。