Molecular Design and Alignment for Ambipolar SCLC Mobility in Self-Assembled Columnar Discogens

Area of Science:

• Organic electronics
• Materials science
• Liquid crystals

Background:

• Next-generation electronics require low-cost organic semiconductors with specific optoelectronic properties.
• Room-temperature discotic liquid crystals (DLCs) offer potential due to their self-assembly into charge-transport channels.

Purpose of the Study:

• To design and synthesize novel room-temperature DLCs using an anthraquinone core.
• To investigate their self-assembly behavior and charge-transport properties for electronic applications.

Main Methods:

• Molecular design utilizing an anthraquinone core with ester-functionalized tri-alkoxy phenyl units.
• Characterization of mesophase behavior and self-assembly using techniques like GISAXS.
• Evaluation of charge transport properties via space charge limited current (SCLC) measurements.

Main Results:

• Synthesized room-temperature DLCs (compounds 1.1-1.3) exhibiting a stable columnar oblique (Colob) mesophase.
• Achieved balanced ambipolar charge transport with high hole and electron mobilities (5.04 and 4.93 cm2 V-1 s-1).
• Demonstrated propensity for homeotropic alignment, crucial for efficient charge carrier movement.

Conclusions:

• The molecular design strategy effectively yields room-temperature DLCs with desirable properties.
• Dipole-dipole interactions and π-π stacking stabilize the mesophase and facilitate charge transport.
• The developed materials show significant promise for solution-processable organic electronic devices.