Au@MoS2@WS2 Core–Shell Architectures: Combining Vapor Phase and Solution-Based Approaches

Solution preparation provides a versatile platform to extend the applications of transition-metal dichalcogenides (TMDs) beyond those achievable with traditional vapor-based preparation methods. However, existing solution-based synthesis and exfoliation approaches present numerous challenges, including low-crystallinity material and incompatibility with complex geometries, particularly with respect to spatial control over interfacial regions. Perhaps interestingly, these disadvantages align well with some of the advantages of vapor phase synthesis. Here, we introduce a strategy that combines vapor phase deposition and solution chemistry to build TMD core–shell heterostructures housed in aqueous media and reap the benefits of both preparation methods. We report a new TMD core–shell heterostructure, Au@MoS2@WS2, with an Au nanoparticle core and MoS2 and WS2 shells and provide a means of suspending the structure in solution to allow for higher order patterning and ligand-based functionalization. High-resolution electron microscopy and Raman spectroscopy provide a detailed analysis of the structure and interfaces of the core–shell heterostructures. UV–vis, dynamic light scattering, and zeta potential measurements exhibit outstanding natural stability and monodispersity of Au@MoS2@WS2 in solution. As a proof of concept, the aqueous environment is utilized to both functionalize the core–shell heterostructures with electrostatic ligands and pattern them into desired configurations on a target substrate. This work harnesses the advantages of vapor phase preparation of nanomaterials and the functionality possible with aqueous suspension to expand future engineering and application opportunities of TMD heterostructures.