Modelling the structural disorder in trigonal-prismatic coordinated transition metal dichalcogenides

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDCs) are layered 2D materials with covalent intralayer and van der Waals (vdW) interlayer bonding.
• Their unique electronic and physical properties drive applications in catalysis, electronics, and energy storage.
• Understanding structural disorder is crucial for optimizing TMDC performance.

Purpose of the Study:

• To develop and validate a structural model for disorder in multilayer TMDCs.
• To investigate the impact of lithium intercalation on the structure of molybdenum disulfide (MoS2).
• To provide a flexible model applicable to various TMDCs and preparation methods.

Main Methods:

• Development of a structural model incorporating stacking faults, atomic displacements, and crystallite size/shape.
• Simulation of X-ray diffraction (XRD) patterns based on the model.
• Fitting simulated XRD patterns to experimental data from lithiated MoS2.

Main Results:

• Determined an average crystallite size of approximately 50 Å with nearly spherical shapes.
• Quantified deviations from the ideal eclipsed atomic arrangement due to structural disorder.
• Observed increased interlayer distances and correlated atomic displacements attributed to lithium intercalation.

Conclusions:

• The developed model accurately describes structural disorder in multilayer TMDCs, specifically lithiated MoS2.
• Lithium intercalation significantly alters the interlayer and intralayer atomic arrangements.
• The model's flexibility allows for its application to diverse TMDCs and synthesis routes.