Through integrating hydrophobic and hydrophilic segment into the block copolymer, we developed organic electrochemical transistors with sufficiently good performance and suppressed water swelling/doping. This offers an approach to enhance the sensitivity to ion and dopamine in aqueous electrolytes.

Abstract

Organic electrochemical transistors (OECTs) with mixed ionic‒electronic transport features have demonstrated significant potential in biosensing applications. Semiconductor polymers grafted with hydrophilic side chains have notably enhanced performance and applications. However, water-induced overswelling and doping in biocompatible aqueous environments hinder high-sensitivity detection. In this study, we introduce two block copolymers, DPP-b-Pg2T-T and NDI-b-Pg2T-T, which integrate both hydrophobic and hydrophilic segments to achieve balanced ionic–electronic conductivities and the sensing performance. These materials effectively suppress swelling and water doping, resulting in low noise signals in aqueous electrolytes. Consequently, devices based on two polymer materials exhibit superior ion concentration variation performance and enhanced sensing capabilities, with an improved sensitivity to dopamine (DA) of up to 266 mV dec⁻¹.