Preprocessing Affords 3D Crystalline Poly(3-hexylthiophene) Structure

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Poly(3-hexylthiophene-2,5-diyl) (P3HT) is a key material for organic field-effect transistors (OFETs).
• Solution processing and deposition significantly impact P3HT aggregation and crystallization.
• Controlling molecular ordering is crucial for optimizing charge transport in OFETs.

Purpose of the Study:

• To investigate the effect of vibration-assisted convective deposition on P3HT film morphology and OFET performance.
• To compare vibration-assisted convective deposition with other common deposition techniques.
• To understand the relationship between processing, molecular ordering, and device characteristics.

Main Methods:

• Fabrication of OFETs using P3HT active layers.
• Comparison of spin coating, blade coating, convective deposition, and vibration-assisted convective deposition.
• Characterization using ultraviolet-visible spectroscopy and grazing-incidence wide-angle X-ray scattering (GWAXS).

Main Results:

• Vibration-assisted convective deposition promotes intrachain interactions, longer conjugation length, and polymer backbone planarization.
• Pre-processing (sonication and aging) combined with vibration-assisted deposition leads to J-like aggregation and ordered 3D crystalline structures.
• OFETs fabricated with these optimized films achieved high mobilities up to 0.14 cm² V⁻¹ s⁻¹.

Conclusions:

• P3HT charge transport is highly sensitive to intramolecular interactions and backbone planarity.
• Vibration-assisted deposition is an effective technique for controlling P3HT aggregation and crystallization.
• Optimized processing leads to enhanced molecular ordering and improved OFET performance.