Anisole Processible n‐Type Conjugated Polymers Synthesized via C─H/C─H Oxidative Direct Arylation Polycondensation for Organic Electrochemical Transistors

The development of n-type polymers for organic electrochemical transistors (OECTs) has lagged significantly behind their p-type counterparts. Moreover, these polymers are often synthesized via Stille polycondensation. Herein, three polymers with thiazole-flanked diketopyrrolopyrrole is synthesized as the monomer through C─H/C─H oxidative direct arylation polycondensation (Oxi-DArP). This protocol employs unfunctionalized (C─H terminated) monomers, and the generated byproducts are environmentally benign. The electron-deficient polymer backbone confers these polymers with LUMO energy levels below -4.20 eV, enabling all of them to exhibit n-type behavior in OECTs. Additionally, the resulting polymers are soluble in the green solvent anisole. With an optimized alkyl spacer between oligo(ethylene glycol) side chain and conjugated backbone, the polymer gTzDPP-C8 showed the best device performance with geometry normalized transconductance (g_m,norm) up to 6.31 S cm^-1 and µC^* up to 23.1 F V^-1 cm^-1 s^-1. This work has successfully proved that C─H/C─H Oxi-DArP is a promising method for synthesizing n-type OMIECs to fulfill high-performance OECTs.