An Efficiently Doped PEDOT:PSS Ink Formulation via Metastable Liquid-Liquid Contact for Capillary Flow-Driven,...

Area of Science:

• Materials Science
• Polymer Chemistry
• Organic Electronics

Background:

• Flexible electronics require high-performance polymers like poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS).
• Existing methods for enhancing PEDOT:PSS conductivity face challenges in efficiency, stability, and biocompatibility.

Purpose of the Study:

• To develop a scalable and efficient method for fabricating conducting PEDOT:PSS inks.
• To investigate the self-assembly of PEDOT:PSS films with controlled morphology and enhanced electrical properties.

Main Methods:

• A metastable liquid-liquid contact (MLLC) method was employed for scalable PEDOT:PSS ink fabrication, enabling simultaneous phase separation and excess poly(styrene sulfonate) (PSS) removal.
• Ring-like PEDOT:PSS films were prepared via controlled droplet evaporation, balancing the coffee-ring effect and Marangoni vortex.
• Morphology and electrical properties of the films were characterized.

Main Results:

• The MLLC method yielded PEDOT:PSS inks with significantly improved conductivity.
• Tunable ring-like morphologies and preferentially interconnected nanofibril networks were achieved.
• A high electrical conductivity of 6,616 S cm⁻¹ and excellent optical transparency were obtained.

Conclusions:

• The MLLC method offers a simple, efficient, and scalable approach for doping commercial PEDOT:PSS inks.
• The self-assembled deposition pattern provides a promising route for organic semiconductor films in flexible electronics, bioelectronics, and photovoltaics.
• The resulting PEDOT:PSS films demonstrated potential as electrodes for touch sensors with gradient pressure sensitivity.