A Highly Conductive n-Type Conjugated Polymer Polymerized in Water

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a benchmark hole-transporting (p-type) polymer that finds applications in diverse electronics devices. Most of its success is due to its facile synthesis in water, exceptional water processability, and outstanding electrical performance. Applications in fields like bioelectronics and thermoelectric devices often necessitate the complementary use of both p-type and n-type (electron-transporting) materials. However, the availability of n-type materials amenable to water-based polymerization and processing remains limited. Here, we present a novel synthesis method enabling direct polymerization in water, yielding a highly conductive, water-processable n-type conjugated polymer. By adjusting the synthetic procedure and use of surfactants, we achieve an impressive conductivity of up to 66 S/cm (with an average of 48 ±18 S/cm), ranking among the highest for n-type polymers processed using green solvents. The new n-type polymer also exhibits outstanding stability, maintaining 89% of its initial conductivity after 146 days of storage in air. Our synthesis approach, along with the novel polymer it yields, promises significant advancements in the field of printed electronics.