High-Performance n-Type Polymeric Mixed Ionic-Electronic Conductors: The Impacts of Halogen Functionalization.

Developing high-performance n-type polymer mixed ionic-electronic conductors (PMIECs) is a grand challenge, which largely determines their applications in organic electronic devices based on logic circuits and p-n junctions, such as organic electrochemical transistors (OECTs) and organic thermoelectrics (OTEs). Herein, we report two halogen-functionalized PMIECs f-BTI2g-TVTF and f-BTI2g-TVTCl built from fused bithiophene imide dimer (f-BTI2) bearing branched oligo(ethylene glycol) side chain as the acceptor unit and halogenated thienylene-vinylene-thienylene (TVT) as the donor co-unit. Compared to the control polymer f-BTI2g-TVT, the fluorinated f-BTI2g-TVTF shows lower-positioned LUMO, improved charge transport property, and greater ion uptake capacity. As a result, f-BTI2g-TVTF delivers a state-of-the-art μC * of 90.2 F cm -1 V -1 s -1 with a remarkable electron mobility of 0.41 cm 2 V -1 s -1 in OECTs and an excellent power factor of 64.2 μW m -1 K -2 in OTEs, higher than those of f-BTI2g-TVTCl and parent f-BTI2g-TVT. Using f-BTI2g-TVTF, we further demonstrate an OECT-based inverter amplifier with voltage gain up to 148 V V -1 , which is among the highest values for OECT inverters. Such results shed light on the impacts of halogen atoms for developing high-performing n-type PMIECs and pave the way for realizing highly efficient n-type OECT and OTE devices. This article is protected by copyright. All rights reserved.