Microcrystallization of a Solution-Processable Organic Semiconductor in Capillaries for High-Performance Ambipolar...

Area of Science:

• Materials Science
• Organic Electronics
• Crystallography

Background:

• Organic semiconductors are crucial for developing flexible and low-cost electronic devices.
• Controlling crystal morphology and alignment is key to optimizing charge transport properties.
• Quinoidal quaterthiophene derivatives (QQT(CN)4) exhibit promising ambipolar charge transport characteristics.

Purpose of the Study:

• To develop a method for fabricating patterned crystalline microstructures of QQT(CN)4.
• To evaluate the charge transport properties of these microstructures.
• To demonstrate control over crystal size and array formation.

Main Methods:

• Microcrystallization in capillaries using polydimethylsiloxane (PDMS) molds (open- and closed-).
• Fabrication of thin film microstructures from QQT(CN)4 chloroform solutions.
• Fabrication and characterization of bottom-gate top-contact transistors.

Main Results:

• Aligned needle-shaped QQT(CN)4 crystals were successfully formed in patterned microstructures.
• Achieved high hole mobility (0.17 cm² V⁻¹ s⁻¹) and electron mobility (0.083 cm² V⁻¹ s⁻¹).
• Demonstrated control over crystal size and microline array formation by adjusting PDMS mold structure and solution concentration.

Conclusions:

• Microcrystallization in capillaries is an effective technique for simultaneously patterning organic needle single crystals and controlling crystallization.
• The method offers a simple and versatile approach for fabricating high-performance organic electronic devices.
• Results approach mobilities seen in individual QQT(CN)4 single crystal microneedles.