Unveiling Charge-Transport Mechanisms in Electronic Devices Based on Defect-Engineered MoS₂ Covalent Networks.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Solution-processed 2D semiconductors in printed electronics face limitations due to structural defects and high interflake junction resistance.
• Covalently interconnected networks of transition metal dichalcogenides offer a potential solution to simultaneously address these limitations.
• Systematic research into charge-transport properties of these covalently linked systems is lacking.

Purpose of the Study:

• To unveil the charge-transport mechanisms in printed devices based on covalent molybdenum disulfide (MoS2) networks.
• To compare the effects of aromatic versus aliphatic dithiolated linkers on charge transport.
• To provide guidelines for optimizing MoS2 devices utilizing covalent networks.

Main Methods:

• Multiscale analysis of charge-transport mechanisms in printed MoS2 devices.
• Temperature-dependent electrical measurements to identify dominant transport mechanisms.
• Percolation theory analysis and density functional calculations to understand linker effects.

Main Results:

• Hopping is the dominant charge transport mechanism in these MoS2 networks.
• Aliphatic linkers result in 3D variable range hopping, while aromatic linkers exhibit nearest neighbor hopping.
• Devices with π-conjugated (aromatic) molecules show superior performance due to enhanced interflake connectivity and additional percolation paths.

Conclusions:

• Covalent MoS2 networks significantly improve charge transport in printed electronics.
• Aromatic linkers are more effective than aliphatic linkers for enhancing device performance.
• Understanding linker-dependent charge transport mechanisms is crucial for designing advanced MoS2-based devices.