n-Type organic semiconducting polymers: stability limitations, design considerations and applications

Area of Science:

• Materials Science
• Organic Electronics
• Semiconductor Physics

Background:

• N-type organic semiconductors (OSCs) are crucial for organic electronics but suffer from ambient operational instability.
• This instability is primarily due to oxidation by water and oxygen, requiring deep LUMO levels (<-4 eV) for stability.

Purpose of the Study:

• To review design strategies for high-performance n-type OSCs in organic thin-film transistors (OTFTs), organic electrochemical transistors (OECTs), and organic thermoelectrics (OTEs).
• To discuss limitations, measurement challenges, and synthetic methods to overcome instability.

Main Methods:

• Review of existing literature on n-type OSC design principles and performance metrics.
• Analysis of synthetic modifications enhancing performance, including backbone design, functionalization, and structural modifications.

Main Results:

• Identified key design strategies: electron-deficient backbones, electron-withdrawing groups, heteroatoms, rigidification, planarization, and increased conjugation length.
• Detailed recent high-performing n-type materials for OTFT, OECT, and OTE applications.

Conclusions:

• Fundamental synthetic design principles are crucial for developing stable and high-performing n-type OSCs.
• This review provides a roadmap for future advancements in n-type OSC materials.