• Jin, Wenlong
• Rashid, Reem B.
• Rivnay, Jonathan
• Ji, Xudong
• Costantini, Giovanni
• Wu, Ruiheng
• Griggs, Sophie
• Moser, Maximilian
• Bristow, Helen
• Chen, Xingxing
• Gasparini, Nicola
• Wu, Xiaocui
• Strzalka, Joseph
• Mcculloch, Iain
• Paulsen, Bryan D.
• Fabiano, Simone
• Meli, Dilara

Abstract

A series of fully fused n-type mixed conduction lactam polymers p(g7NCnN), systematically increasing the alkyl side chain content, are synthesized via an inexpensive, nontoxic, precious-metal-free aldol polycondensation. Employing these polymers as channel materials in organic electrochemical transistors (OECTs) affords state-of-the-art n-type performance with p(g7NC10N) recording an OECT electron mobility of 1.20 * 10-2 cm2 V-1 s-1 and a muC* figure of merit of 1.83 F cm-1 V-1 s-1. In parallel to high OECT performance, upon solution doping with (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethylamine (N-DMBI), the highest thermoelectric performance is observed for p(g7NC4N), with a maximum electrical conductivity of 7.67 S cm-1 and a power factor of 10.4 muW m-1 K-2. These results are among the highest reported for n-type polymers. Importantly, while this series of fused polylactam organic mixed ionic-electronic conductors (OMIECs) highlights that synthetic molecular design strategies to bolster OECT performance can be translated to also achieve high organic thermoelectric (OTE) performance, a nuanced synthetic approach must be used to optimize performance. Herein, we outline the performance metrics and provide new insights into the molecular design guidelines for the next generation of high-performance n-type materials for mixed conduction applications, presenting for the first time the results of a single polymer series within both OECT and OTE applications.

Topics

• impedance spectroscopy
• polymer
• mobility
• electrical conductivity