Fused Bithiophene Imide Dimer-Based n-Type Polymers for High-Performance Organic Electrochemical Transistors.

The development of n-type organic electrochemical transistors (OECTs) lags far behind their p-type counterparts. In order to address this dilemma, we report here two new fused bithiophene imide dimer (f-BTI2)-based n-type polymers with a branched methyl end-capped glycol side chain, which exhibit good solubility, low-lying LUMO energy levels, favorable polymer chain orientation, and efficient ion transport property, thus yielding a remarkable OECT electron mobility (μe ) of up to ≈10-2  cm2  V-1  s-1 and volumetric capacitance (C*) as high as 443 F cm-3 , simultaneously. As a result, the f-BTI2TEG-FT-based OECTs deliver a record-high maximum geometry-normalized transconductance of 4.60 S cm-1 and a maximum μC* product of 15.2 F cm-1  V-1  s-1 . The μC* figure of merit is more than one order of magnitude higher than that of the state-of-the-art n-type OECTs. The emergence of f-BTI2TEG-FT brings a new paradigm for developing high-performance n-type polymers for low-power OECT applications.