Hybrid chalcogenide nanoparticles: 2D-WS2 nanocrystals inside nested WS2 fullerenes

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Chemistry

Background:

• Layered metal chalcogenides, like tungsten disulfide (WS2), exhibit unique properties.
• Inorganic fullerenes offer novel structural possibilities compared to carbon fullerenes.
• Controlling the synthesis of nanostructured materials is crucial for advanced applications.

Purpose of the Study:

• To synthesize nested WS2 inorganic fullerenes (IF-WS2) using Metalorganic Chemical Vapor Deposition (MOCVD).
• To investigate the internal structure and formation mechanism of IF-WS2.
• To explore the potential of IF-WS2 for enhanced tribological activities.

Main Methods:

• MOCVD synthesis assisted by iodine to enhance surface diffusion.
• Transmission Electron Microscopy (TEM) for monitoring fullerene growth.
• Focused Ion Beam (FIB) cross-sectioning and Scanning Electron Microscopy (SEM) for internal structure analysis.
• Atomic Force Microscopy (AFM) for shell strength measurement.

Main Results:

• Nested IF-WS2 were successfully synthesized.
• Lamellar reaction intermediates were observed within the fullerene particles.
• WS2 exhibits a preference for planar structures, with edge dangling bonds stabilized by sulfur.
• The strength of the WS2 shell was quantified.
• Encapsulated lamellar structures were identified as potential contributors to tribological performance.

Conclusions:

• The study demonstrates a viable MOCVD route for nested IF-WS2 synthesis.
• The presence of lamellar intermediates suggests a unique growth mechanism.
• The findings indicate that IF-WS2 possess properties suitable for advanced tribological applications.