Long-term synaptic plasticity simulated in ionic liquid/polymer hybrid electrolyte gated organic transistors

Owing to their potential advantages such as low-temperature processing, low-cost fabrication, large-area production, and mechanical flexibility, organic electrochemical transistors (OECTs) have gained considerable attention for bioelectronics. In this paper, we report on the fabrication of organic poly(3-hexylthiophene) (P3HT) synaptic transistors gated by the ionic liquid/poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] hybrid electrolyte. Because the formation of electric-double-layers (EDLs) can provide strong capacitive coupling within the boundary layer of hybrid electrolyte/P3HT channel interface, these organic devices exhibit low operating voltage and large hysteresis windows. The most important is that the bio-neural functions at synaptic domain including excitatory post-synaptic current (EPSC) and long-term synaptic plasticity were demonstrated. Under high gate presynaptic spike (|V-pre| = 2.0 V), an obvious non-volatile EPSC behaviors are observed, which are mainly due to an irreversible electrochemical doping effect. The hybrid electrolyte gated organic synaptic transistors provide a potential candidate for building neuromorphic systems. (C) 2017 Elsevier B.V. All rights reserved.