Composition‐Dependent Wide‐Range Tunability of Optical and Electronic Properties in SnS _x Se _(2‐x) Alloy Nanosheets

ABSTRACT Isovalent alloying in printable metal dichalcogenide nanomaterials enables precise, application‐targeted property tuning. However, a scalable platform offering broad optical and electrical tunability has so far remained elusive. Herein, we establish a powder‐based, solution‐processed route to access the full domain of SnS _x Se _(2‐x) alloy nanosheets, providing control over a wide range of properties through chalcogenide composition. The n‐type nanosheet alloy series shows a wide spread in optical and in‐plane electrical properties, ranging from 1.67 eV and low bandgap metallic‐like behavior for 2D SnSe ₂ , to 2.46 eV and wide bandgap semiconducting behavior with high‐resistivity for 2D SnS ₂ . The out‐of‐plane conductivity is also tunable, showing nonmonotonic behavior with an optimal chalcogenide ratio of x = 1.2 – 1.6. Using photoelectrochemistry as an example, we highlight how the interplay of these tunable properties enables optimized performance for targeted applications. The exceptional range of tailorable properties reported here provides a roadmap for tuning these alloys, thereby opening avenues for their potential application in a multitude of fields.