Engineering donor-acceptor conjugated polymers for high-performance and fast-response organic electrochemical transistors†

To date, high-performance organic electrochemical transistors (OECTs) have mostly been based on polythiophene systems. Donor-acceptor (D-A) conjugated polymers are expected to be promising materials for OECTs owing to their high mobility and comparatively low crystallinity (good for ion diffusion). However, the OECT performance of D-A polymers lags far behind that of the polythiophenes. Here we synergistically engineered the backbone and side chain of a series of diketopyrrolopyrrole (DPP)-based D-A polymers and found that redox potential, molecular weight, solution processability, and film microstructures all have a severe impact on their performance. After systematic engineering, P(bgDPP-MeOT2) exhibited the best figure-of-merit (mu C*) of 225 F cm(-1) V-1 s(-1), amongst the highest performance of the reported D-A polymers. Besides, the DPP polymers exhibited high hole mobility of over 1.6 cm(2) V-1 s(-1), leading to fast response OECTs with a record low turn-off response time of 30 mu s. The polymer also exhibited good operation stability with a current retention of 98.8% over 700 electrochemical switching cycles. This work reveals the complexity and systematicness in the development of D-A polymer based high-performance OECTs.

Automated summary

High-performance organic electrochemical transistors (OECTs) using donor-acceptor (D-A) conjugated polymers show promising potential, but their performance lags behind polythiophene systems. By engineering the backbone and side chain of a series of diketopyrrolopyrrole (DPP)-based D-A polymers, researchers achieved improved performance with high figure-of-merit and fast response time. This work highlights the complexity and systematic approach required for developing high-performance OECTs based on D-A polymers.