Shape-Engineered Synthesis of Atomically Thin 1T-SnS₂ Catalyzed by Potassium Halides

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Shape engineering is vital for tuning the properties of 2D layered metal dichalcogenides (LMDs).
• Controllable synthesis of 1T phase tin disulfide (SnS₂) with varied morphologies is challenging.

Purpose of the Study:

• To develop a facile method for synthesizing large-size, uniform, atomically thin 1T-SnS₂ with diverse morphologies.
• To investigate the role of potassium halides in controlling SnS₂ growth and phase.

Main Methods:

• Chemical vapor deposition (CVD) with potassium halide additives.
• Density functional theory (DFT) calculations to understand growth mechanisms.
• Characterization of SnS₂ morphology and properties.

Main Results:

• Achieved controlled synthesis of 1T-SnS₂ with morphologies including hexagon, triangle, windmill, dendritic, and coralloid.
• Demonstrated that Sn concentration and growth conditions dictate morphology.
• Potassium halides enhance in-plane growth of monolayer SnS₂ by reducing surface migration barriers and increasing adhesion.
• Branched SnS₂ structures with higher fractal dimensions showed improved performance in hydrogen evolution reactions.
• Established that potassium halides favor 1T-phase LMDs, while sodium halides favor 2H-phase.

Conclusions:

• A general approach for controllable-phase synthesis of 2D LMD crystals and heterostructures was developed.
• Shape engineering of 2D materials offers a strategy for property tuning in demanding applications.
• The study provides a pathway for optimizing SnS₂ for applications like hydrogen evolution.