Directed crystallization of a poly(3,4-ethylenedioxythiophene) film by an iron(III) dodecyl sulfate lamellar superstructure
Feng Ma, Sang‐Il Choi, Dooyong Lee, Sung Bae Jeon, Sungkyun Park, Sung-Pyo Cho, Jin‐Hyo Boo, Sung-Soo Kim
Abstract
Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a successfully commercialized polymeric semiconductor material, has potential as a transparent electrode in flexible electronic devices, yet has insufficient conductivity. We present the synthesis, properties, and directed crystallization of the PEDOT:dodecyl sulfate (PEDOT:DS) film. Iron(III) dodecyl sulfate (Fe(DS)3) multi-lamellar vesicles (MLVs), a new growth template, are used to synthesize and direct the growth of the PEDOT:DS film via vapor-phase polymerization of 3,4-ethylenedioxythiophene to form huge PEDOT:DS co-crystal domains within the MLV superstructure. The polycrystalline film has metallic conductivity (avg. ~1.0 × 104 S cm−1), is highly transparent and mechanically durable yet flexible, and suitable for next-generation flexible electronics. These noteworthy properties are conferred by the MLV lamellar superstructure of Fe(DS)3, a selective oxidant and an efficient in situ dopant that enhances the film hydrophobicity and durability. Sophisticated MLV-type oxidants are foreseen to enable the synthesis of more conductive, transparent, robust, flexible, and water-stable polymer electrode materials in future. PEDOT:PSS is a conductive polymer with potential as electrodes in flexible electronics, but conductivity is not always satisfactory. Here, the authors report the use of dodecyl sulfate in place of polystyrene sulfonate to prepare a durable and conductive film with large crystal domains.