Fabrication of covalently bonded MoS₂–graphene heterostructures with different organic linkers

Achieving stable and reliable 2D-2D van der Waals heterostructures remains challenging. The broadest strategy for synthesizing these heterostructures is growth or manually stacking one material on top of the other, yet it is inefficient. Here, we present a strategy for synthesizing covalently bonded MoS₂-graphene heterostructures using organic linkers with two anchor sites at a low cost. Our covalent heterostructures exhibit a more homogeneously alternating structure than the corresponding randomly alternating structure of vdW heterostructures, as confirmed by surface-enhanced Raman spectroscopy (SERS) measurements. Moreover, different linkers can be used to adjust the interlayer distance between graphene and MoS₂, leading to significant impacts on their optical and electrochemical properties, including Photoluminescence (PL), cyclic voltammetry (CV), Ultraviolet-visible spectroscopy (UV-Vis), and SERS. Our strategy offers opportunities to advance fundamental research and enable the practical application of 2D/2D van der Waals heterostructures in various fields, including optoelectronics, energy storage, and catalysis.