Electrostatic Ion Trapping in Organic Electrochemical Transistors for Record Neuromorphic Memory Performance

Organic electrochemical transistors (OECTs) leverage the chemical tunability of polymeric semiconductors; however, their potential as memory devices remains constrained by insufficient ion retention. Previous studies on physical trapping of ions within polymer crystalline domains have generally reported memory windows below 5.3 V. Here, we achieve molecular-level hysteresis control by designing a dual-functional zwitterionic crosslinker that creates an electrostatic ion-trapping channel. Its fixed anionic sulfonate group establishes a repulsive barrier to delay ion injection, while its cationic ammonium site forms a deep electrostatic trap that creates a 2.03 eV barrier, thereby stabilizing the doped state, and collectively producing pronounced hysteresis. GIWAXS under sequential biasing reveals reversible lamellar dynamics, enabled by ionic interactions among side-chain-tethered zwitterion units. The resulting OECTs achieve record hysteresis strength (96.4 V) and memory window (8.65 V) while maintaining an on/off ratio ∼10⁶ and 86.4% conductance retention after 200,000 pulses. Moreover, the Z-FPA scheme generalizes to other polymer semiconductors, providing a polymer-agnostic route to high-fidelity neuromorphic OECTs. Synaptic metrics are more symmetric; device-informed models reach 92.87% on MNIST, and ECG reservoir computing confirms biosignal compatibility. Our findings provide key molecular insights into the material design and operating mechanisms critical for advancing next-generation neuromorphic OECTs.