Dynamically Reconfigurable Short-Term Synapse with Millivolt Stimulus Resolution Based on Organic Electrochemical Transistors

Electrolyte-gated organic electrochemical transistors (OECTs) are attractive for synaptic electronics owing to the ionic–electronic coupling, huge specific capacitance, physiological environmental compatibility, and architectural flexibility. Here, an identical spike-polarity method is reported to realize the concomitance of excitatory and inhibitory short-term plasticities in unipolar poly(3,4-ethylenedioxythiophene)–poly(styrenesulphonate) (PEDOT:PSS) OECTs. Dynamical reconfiguration between the excitatory and inhibitory responses with multilevel and well-balanced synaptic strength is realized, without performing operations or introducing additional modulation terminals. Owing to the distinctive volumetric capacitance of OECTs, the PEDOT:PSS synapse affords remarkable characteristics such as an ultrahigh stimulus-resolution capability of 10 mV and an ultralow power consumption of ≈2 pJ per spike. Moreover, spatiotemporal-correlated logics is realized. This work demonstrates on-demand manipulation of ionic dynamics for building synaptic elements with sophisticated functionalities at a single-device level.