Morphology controlled synthesis of low bandgap SnSe₂ with high photodetectivity

Engineering the properties of layered metal dichalcogenides (LMDs) requires stringent control of their morphology. Herein, using a scalable one-step solvothermal technique, we report the synthesis of SnSe2 under two different conditions, leading to the formation of nanoflakes and nanoflowers. The use of oleic acid in the reaction leads to the formation of nanoflowers, and the presence of ethanol in the reaction medium leads to the formation of nanoflakes. Ab initio density functional theory calculations rationalise this observation, revealing a stronger adsorption of ethanol on the {0001} facet compared to the acid. Furthermore, these SnSe2 nanoflakes, when integrated with graphene, also respond to incident electromagnetic radiation, from the visible to near infrared regime, with a specific detectivity of ∼5 × 1010 Jones, which is comparable to that of the best available photodetectors, making them suitable for use in various technological applications.