High-Mobility Chalcogenophene-Engineered Diketopyrrolopyrrole Mixed Ionic-Electronic Conductors With Doping Tolerance for Low-Power Organic Electrochemical Transistors.

Optimizing the steady-state performance of organic electrochemical transistors (OECTs) requires simultaneous control over both molecular-level design and structural ordering in organic mixed ionic-electronic conductors (OMIECs). Here, we report a series of diketopyrrolopyrrole (DPP)-based polymers functionalized with aliphatic-glycol hybrid side chains (PDPP-4EG-T2 and PDPP-4EG-Se2) and systematically investigate the impact of their structure on OECT performance. In particular, the substitution of chalcogen units (biselenophenes) in the polymer backbone significantly enhances backbone planarity, polarizability, and quinoidal character, thereby improving π-electron delocalization and reinforcing π-π stacking interactions under doping. As a result, PDPP-4EG-Se2 achieves a superior hole mobility of 9.8 cm2 V- 1 s- 1 and a µC* of 786 F cm- 1 V- 1 s- 1 with enhanced operational stability in p-type OECTs. By employing PDPP-4EG-Se2 as a unified material for both electrode and channel components, we construct unipolar inverters and integrate them into a ring oscillator circuit, achieving a high gain value per dynamic power consumption (45.3 V/V nW- 1) alongside with a reliable inverter performance (gain = 40.6 V/V). This study underscores the importance of a doping-tolerant quinoidal framework and tailored molecular-level structural arrangement for achieving high OECT performance with a superior hole mobility.