Surface Engineering of Chemically Exfoliated MoS2 in a "Click": How To Generate Versatile Multifunctional Transition Metal Dichalcogenides-Based Platforms

The development of functional layered two-dimensional (2D) transition metal dichalcogenides (TMDs, e.g., MoS2,WSe2, and MoTe2) as inorganic substitutes of graphene have recently gained great attention due to their wide range of applications. To date, several surface functionalization strategies of MoS2 have been reported to improve processability and chemical reactivity of these 2D inorganic flakes. However, much work has still to be done in order to bridge the gap between the wealthy exohedral functionalization chemistry of carbon-based 2D networks and that of TMDs. Following our experience on post-synthetic modification (PSM) of organic (carbon nanotubes, CNTs) and organic-inorganic networks (metal-organic frameworks, MOFs) under CuI mediated azide-alkyne cycloaddition protocol, we have found a convenient and highly efficient methodology for the decoration of MoS2 nanosheets with aryl-azido groups and their post-synthetic modification via "click chemistry" using single terminal acetylenes or defined binary acetylene mixtures generating homo- and hetero-decorated MoS2 platforms. The successful functionalization and post-derivatization of MoS2 samples have been systematically followed through the main physicochemical (SEM microscopy, fluorescence lifetime imaging), spectroscopic (IR, Raman, XPS, UV-vis), and analytical techniques. Overall, this study will represent a milestone in the simple and highly versatile MoS2 nanosheet engineering, offering a convenient approach to confer multimodality to this new and emerging class of 2D inorganic materials widening their applicability range in several technological fields.