Vertically Phase-Separated PEDOT:PSS Film via Solid-Liquid Interface Doping for Flexible Organic Electrochemical...

Area of Science:

• Organic electronics
• Bioelectronics
• Materials science

Background:

• Organic electrochemical transistors (OECTs) are key in organic bioelectronics.
• Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a high-performance channel material.
• Uniform PEDOT:PSS structure limits ion penetration and charge transport balance.

Purpose of the Study:

• To engineer a novel PEDOT:PSS film structure for enhanced OECT performance.
• To improve the balance between ion penetration and charge transport in OECT channels.
• To provide guidelines for designing advanced OECT channel materials.

Main Methods:

• Fabrication of a novel PEDOT:PSS film with a vertical phase separation structure (VPSS-P).
• Characterization of the VPSS-P film's structure, electrochemical stability, and contact resistance.
• Fabrication and testing of flexible OECT devices utilizing the VPSS-P channel.

Main Results:

• VPSS-P film exhibits PSS accumulation at the surface and PEDOT enrichment at the bottom.
• Achieved high transconductance (70.5 mS) and a high product of mobility and volumetric capacitance (μC* ~ 479 F cm⁻¹ V⁻¹ s⁻¹).
• Demonstrated ultralow contact resistance (~0.79 Ω cm) and robust performance in flexible OECTs under deformation.

Conclusions:

• The VPSS-P structure significantly enhances OECT performance and electrochemical stability.
• This novel structure offers a pathway to overcome limitations in traditional PEDOT:PSS channels.
• Findings pave the way for next-generation high-performance organic transistors and flexible electronics.