Stretchable Redox-Active Semiconducting Polymers for High-Performance Organic Electrochemical Transistors

Area of Science:

• Bioelectronics
• Materials Science
• Polymer Chemistry

Background:

• Organic electrochemical transistors (OECTs) offer high amplification and sensitivity for bioelectronic applications.
• Achieving seamless tissue-electronics interfaces requires soft, stretchable OECTs, which are limited by the lack of suitable semiconducting polymers.
• Current OECTs lack the necessary skin-like properties for advanced bio-integrated sensing.

Purpose of the Study:

• To develop a novel stretchable semiconducting polymer for high-performance OECTs.
• To create intrinsically stretchable OECTs with enhanced performance and conformability.
• To demonstrate the utility of these stretchable OECTs in wearable bioelectronic applications, such as ECG monitoring.

Main Methods:

• Synthesis and characterization of a new stretchable semiconducting polymer, poly(2-(3,3'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-[2,2'-bithiophen]-5)yl thiophene) (p(g2T-T)).
• Fabrication and testing of OECT devices using the developed polymer, evaluating performance under various strain conditions.
• Systematic characterization of polymer design features (backbone architecture, side-chain density, molecular weight) influencing stretchability and electronic properties.

Main Results:

• The synthesized polymer, p(g2T-T), exhibits exceptional stretchability (>200% strain) and durability (5000 cycles).
• OECTs fabricated with p(g2T-T) demonstrate performance comparable to state-of-the-art non-stretchable devices, with high normalized transconductance (≈223 S cm^-1).
• Intrinsically stretchable OECTs achieved up to 100% biaxial strain, and were successfully used for on-skin ECG recording with excellent conformability.

Conclusions:

• A highly stretchable redox-active polymer semiconductor has been successfully developed for advanced OECT applications.
• The unique polymer design enables simultaneous high stretchability and high device performance, overcoming previous limitations in bioelectronics.
• This work paves the way for next-generation, skin-like wearable sensors with integrated amplification for accurate physiological signal monitoring.