n-type rigid semiconducting polymers bearing oligo(ethylene glycol) side chains for high-performance organic electrochemical transistors

N-type conjugated polymers as the semiconducting component of organic electrochemical transistors (OECTs) are still undeveloped with respect to their p-type counterparts. Herein, we report two rigid n-type conjugated polymers bearing oligo(ethylene glycol) (OEG) side chains, PgNaN and PgNgN, which demonstrated an essentially torsion-free π-conjugated backbone. The planarity and electron-deficient rigid structures enable the resulting polymers to achieve high electron mobility in an OECT device of up to the 10^-3  cm²  V^-1  s^-1 range, with a deep-lying LUMO energy level lower than -4.0 eV. Prominently, the polymers exhibited a high device performance with a maximum dimensionally normalized transconductance of 0.212 S cm^-1 and the product of charge-carrier mobility μ and volumetric capacitance C* of 0.662±0.113 F cm^-1  V^-1  s^-1 , which are among the highest in n-type conjugated polymers reported to date. Moreover, the polymers are synthesized via a metal-free aldol-condensation polymerization, which is beneficial to their application in bioelectronics.