Liquid-crystalline semiconducting polymers with high charge-carrier mobility

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Organic electronics require semiconductors with high charge-carrier mobility and stability.
• Microstructure control is crucial for optimizing semiconductor performance.
• Ambient degradation limits the practical application of organic semiconductors.

Purpose of the Study:

• To develop novel semiconducting liquid-crystalline thieno[3,2-b]thiophene polymers.
• To enhance charge-carrier mobility through controlled morphology.
• To evaluate the stability of these polymers in transistor devices under various environmental conditions.

Main Methods:

• Synthesis of new thieno[3,2-b]thiophene polymers.
• Processing of polymers in the liquid-crystalline mesophase to achieve organized morphology.
• Fabrication and characterization of thin-film transistors (TFTs).
• Exposure of devices to ambient and low-humidity air for stability testing.

Main Results:

• Polymers exhibited large crystalline domain sizes (approx. 200 nm) in thin films.
• Processing in the mesophase significantly enhanced charge-carrier mobility.
• Field-effect mobilities of 0.2-0.6 cm(2) V(-1) s(-1) were achieved under nitrogen.
• Transistors demonstrated good stability under static storage and operation in low-humidity air.

Conclusions:

• Thieno[3,2-b]thiophene polymers processed in the mesophase offer a pathway to high-performance organic electronics.
• The achieved morphology supports the potential for single-crystal polymer transistors.
• These materials show promising stability for practical applications in low-humidity environments.