Ionic‐electronic coupling in PEO‐PEDOT/potassium triflate composite films for organic mixed conductivity enhancement

Abstract

AbstractOrganic mixed ionic‐electronic conductors (OMIECs) are organic materials capable of transporting both ionic species and electronic charges, facilitating ionic‐electronic coupling and enhancing electrical conductivity. PEO‐PEDOT/KOTf composite films synthesized in this study demonstrate significant electrical conductivity enhancement due to the ionic‐electronic coupling. The electrical conductivity of PEO‐PEDOT is 7.05 S.cm−1, predominantly arising from the electronic transport of PEDOT polarons with a minor contribution from ionic transport in PEO. However, introducing KOTf into the PEO‐PEDOT matrix at varying concentrations gradually increases electrical conductivity. At a KOTf concentration of 16 wt.%, the electrical conductivity reaches 51.06 S.cm−1. This pronounced enhancement can be primarily due to the ionic‐electronic coupling occurring at the interface between phase‐separated regions within the polymer matrix. The incorporation of KOTf into PEO‐PEDOT was characterized using FTIR spectroscopy. Moreover, our investigation involved X‐ray diffraction and differential scanning calorimetry analysis, which unveiled a notable trend. As the KOTf concentrations increased, the degree of crystallinity in the PEO‐PEDOT/KOTf composite films declined. This observation provides valuable insights into the structural changes occurring within the films as KOTf is integrated. The potential implications of this discovery span across numerous fields, opening exciting possibilities for advancing electronic and energy‐related technologies.