Foldable semi-ladder polymers: novel aggregation behavior and high-performance solution-processed organic...

Area of Science:

• Organic electronics
• Materials science
• Semiconductor physics

Background:

• Developing high-performance organic light-emitting transistors (OLETs) faces challenges in balancing charge transport and light emission.
• Existing organic light-emitting diode (OLED) and organic field-effect transistor (OFET) materials show limited success in OLET applications.
• Clear design strategies and structure-performance relationships for advanced OLET materials are lacking.

Purpose of the Study:

• To investigate cross-conjugated weak acceptor-weak donor copolymers for enhanced luminescent properties.
• To understand the structure-property relationships governing OLET performance.
• To achieve high external quantum efficiency (EQE) in OLET devices.

Main Methods:

• Synthesis of cross-conjugated weak acceptor-weak donor copolymers.
• Fabrication of multi-layer OLET devices using solution processing.
• Characterization of material self-assembly and optoelectronic properties.

Main Results:

• Unintentional discovery of coiled foldamer formation with intramolecular H-aggregation in the synthesized copolymers.
• Demonstration of exceptional OLET properties attributed to the foldamer structure.
• Achievement of an impressive external quantum efficiency (EQE) of 6.9% in solution-processed OLET devices.

Conclusions:

• Coiled foldamer structures with intramolecular H-aggregation are key to high-performance OLETs.
• The developed copolymers offer a promising new class of materials for advanced organic electronics.
• This work provides critical insights into structure-property relationships for designing efficient OLET materials.