Metal-Like Conductivity in Acid-Treated PEDOT:PSS Films: Surpassing 15,000 S/Cm.

Abstract

Although poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films with high conductivity have been obtained through conventional organic solvent and acid treatment, their conductivity has not yet exceeded 10000 S/cm. In this paper, by combining blade-coating and treating with high concentration and volatilizable trifluoromethanesulfonic acid (CF₃SO₃H), PEDOT:PSS films with ultrahigh conductivity of 15143 S/cm, comparable to some metals, were prepared. Characterizations of morphology and structure indicate the formation of a perfectly continuous fibrous network structure, highly oriented crystallization, and tightly packed π-π stacking of PEDOT chains after removing a vast amount of PSS, which contributes to boosting the electrical conductivity of the treated PEDOT:PSS film. The distinguished electrical properties and ultrahigh conductivity enable it to replace metal materials as electrodes for "all-polymer" capacitive piezoelectric sensors with outstanding pressure sensitivity. Moreover, by regulating the blade-coating condition, the CF₃SO₃H-treated PEDOT:PSS films exhibit excellent electrochemical performance, which is an ideal channel material in organic electrochemical transistors (OECTs). The CF₃SO₃H-treated PEDOT:PSS film-based OECT devices display a high transconductance of 50.6 ± 5.5 mS and carrier mobility of 9.3 ± 1.5 cm²V^-1s^-1. This study not only provides new insights into the development of a simple and efficient PEDOT:PSS film treatment method but also expands its application in flexible electronics. Especially, the present research offers a useful reference in preparing "all-polymer"-based flexible electronic devices.