Organic electrochemical memories (OECMs) attract attention as a memristor for neuromorphic devices (NMDs) in wearable applications due to their high biocompatibility and low-voltage operation characteristics. However, conventional OECMs exhibit limited flexibility and bending durability. In this study, the all-solid-state OECMs are developed using a flexible and self-supporting electrolyte gel and an ultrathin film substrate. The electrolyte gel is prepared by mixing κ-carrageenan and locust bean gum to enhance gel strength and hydrophilicity. As a result, the developed all-solid-state OECMs operate stably even at a bending radius of 0.75 mm, and show no performance degradation after 1,000 bending cycles at a bending radius of 3.6 mm. Furthermore, the nonlinear parameters (νLTD = −0.13, νLTP = 0.28) remain within the range of ±1, suggesting that the OECMs-implemented NMDs achieves high learning accuracy (over 94% for handwritten character recognition). In summary, these all-solid-state OECMs excel in flexibility, durability, and learning accuracy, and are expected to be applied to the next-generation wearable devices.
MATSUDA et al. (Wed,) studied this question.