Strong Proquinoidal Acceptor Enables High-Performance Ambipolar Organic Electrochemical Transistors

Ambipolar organic electrochemical transistors (OECTs) can simplify manufacturing processes and reduce device footprints, yet their performance still lags behind their p-type and n-type counterparts due to limited molecular design strategies. Here, incorporating strong proquinoidal building blocks effectively addresses this challenge is demonstrated. Using a computational acceptor screening approach, three TBDOPV-based polymers are designed and synthesized: P(bgTBDOPV-T), P(bgTBDOPV-EDOT), and P(bgTBDOPV-MeOT2), all exhibiting ambipolar behavior across various donor moieties. Remarkably, P(bgTBDOPV-EDOT) achieves record-high figure-of-merit (µC*) values, reaching 268 F cm^-1 V^-1 s^-1 for p-type and 107 F cm^-1 V^-1 s^-1 for n-type operations. Additionally, P(bgTBDOPV-EDOT) exhibits low operation voltages (V_Th,p = -0.55 V and V_Th,n = 0.32 V), with fast response times (τ_on/τ_off = 0.48/0.36 ms for p-type and 0.41/0.41 ms for n-type) and enhanced operational stability. Inverter devices based on P(bgTBDOPV-EDOT) show high voltage gains of 173 V/V. Theoretical calculations and data analysis confirm that strong proquinoidal acceptors significantly enhance the delocalization of both positive and negative polarons, offering an effective pathway for higher-performance ambipolar OECT materials.