One‐Step Simultaneous Exfoliation and Covalent Functionalization of MoS₂ by Amino Acid Induced Solution Processes

The covalent functionalization of transition metal dichalcogenides (TMDs) has attracted significant interest because of their novel physicochemical properties for various applications. Herein, we report on amino acid (AA)‐induced solution‐processed simultaneous exfoliation and in situ covalent functionalization of exfoliated molybdenum disulfide (MoS 2 ). Covalent functionalization of MoS 2 with AAs was experimentally validated by various spectrochemical characterization and density functional theory calculations. We find that N terminal binding (NH 2 ) of AAs with sulfur defects on exfoliated MoS 2 is much more favorable than the C terminal binding (COOH). Notably, the MoS 2 flakes have significantly improved biocompatibility with normal intestinal epithelial cell‐6. This exfoliation technique is presented here as general strategy; it is not limited to MoS 2 and may apply to exfoliating other MX 2 compounds of TMDs.