Supramolecular electrostatic functionalization of 1T-MoS₂ based on alkylammonium salts

Chemical functionalization is key for expanding the applicability and manufacturing of 2D materials. The functionalization of exfoliated molybdenum disulfide (MoS₂) can allow tuning its chemical-physical properties or introducing anchoring points for post-functionalization, creating heterostructures, hybrid or stimuli-responsive materials. When choosing a functionalization strategy, key aspects are: achieving a high functionalization yield, using sustainable solvents and reactants, and preserving the favorable material's properties. In this work, we report a supramolecular functionalization strategy for 1T-MoS₂ which exploits the coulombic interactions between the negatively charged material and the positively charged alkylammonium salts. The functionalization, performed in water at room temperature, addresses the requirements of green chemistry. Furthermore, the proposed approach allows high functionalization yields (with an alkylammonium : Mo ratio of 1 : 2.6), while preserving the crystalline phase and conductivity characteristic of 1T-MoS₂. Finally, the functionalization with cholamine permits the covalent post-functionalization of the material, exploiting the reactivity of the primary amine of this alkylammonium salt.