摘要： The atomic-scale Legoland of two-dimensional (2D) materials has become a much-frequented scientific playground, with building blocks aplenty to create and explore virtually unlimited stacking configurations. When two or more individual monolayers are placed together to form an artificial homo- or heterostructure with weakly interacting constituent layers, that is where the real van der Waals (vdW) architecture begins. Such creations offer electronic, optical and magnetic phenomena that are often utterly unlike the monolayer case. One notable example is the emergence of a new type of exciton in which the electron and the hole are spatially located in different layers. While the formation of these ‘interlayer’ or ‘indirect’ excitons is not exclusive to vdW structures, such as transition metal dichalcogenide (TMD) bilayers in which these species have been observed so far, the unique properties of the constituent 2D materials stemming from the intrinsic valley physics and the enhanced Coulomb interactions at the 2D limit make for an exciting research journey. Likewise, the much-discussed idea of high-temperature exciton condensation using long-lived interlayer excitons remains a possibility that is yet to be experimentally explored. In contrast to monolayers, vdW layered structures possess an additional degree of freedom: the twist angle that stems from the sensitive dependence of the exciton properties on the interlayer interaction and the structural alignment of the constituent monolayers. This unique feature is of particular importance from the perspective of practical applications as it offers a new means of engineering and manipulation of interlayer excitons.