Circular Flow Alignment of Polymeric Semiconductor Thin Films on Air-Liquid Interfaces

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Science

Background:

• Orientational control of polymeric semiconductors (PSs) is crucial for optimizing carrier transport.
• Current solution-based fabrication methods struggle with scalability and reproducibility due to convection flows during solvent evaporation.

Purpose of the Study:

• To develop a novel, scalable, and facile method for achieving controlled orientation in PS thin films.
• To investigate the impact of this new alignment method on the structural and electronic properties of PS thin films.

Main Methods:

• A circular flow alignment technique was developed, utilizing flowing glycerol to guide PS solutions at the air-liquid interface.
• Thin films were characterized using X-ray diffraction, optical absorption, and carrier mobility measurements in field-effect transistors.

Main Results:

• The circular flow alignment method effectively aligned PS main chains along the flow direction, mitigating convection effects.
• Anisotropic structural and optical properties were observed, confirming uniaxial alignment.
• Field-effect transistors fabricated with these films exhibited a carrier mobility of 0.13 cm^2 V^-1 s^-1, four times higher than spin-coated films.

Conclusions:

• The proposed circular flow alignment method offers a scalable and reproducible approach for fabricating highly aligned PS thin films.
• This technique holds significant potential for advancing applications requiring controlled carrier transport in organic electronics.