Organic Electrochemical Transistors for Neuromorphic Devices and Applications

Neuromorphic engineering, an interdisciplinary field bridging bioelectronics and neuroscience, endeavors to address the bottleneck of the von Neumann architecture by constructing hardware-level artificial neural networks (ANNs) and replicate the complicated architecture and functionality of the human brain, heralding a new era of intelligent sensing, processing, and computing systems. Organic electrochemical transistors (OECTs), which operate via the bulk doping of organic mixed ionic-electronic conductors, are emerging as promising platforms for neuromorphic devices that emulate neuronal and synaptic activities while seamlessly integrating with biological systems. OECTs offer several advantages, including compatibility with flexible and stretchable substrates, tunable ionic and electronic conductivity, multimodal sensing capability, and operation at low voltages. This review aims to provide a comprehensive and state-of-the-art vista of the rapidly advancing field of OECT-based neuromorphic devices, including organic electrochemical neurons, organic electrochemical synapses, and their integrated devices. Particular emphasis is placed on their ability to perform neuromorphic functions and diverse applications in neuromorphic computing and flexible biointerfaces. Conclusions, remaining challenges, and future prospects for the development of OECT-based neuromorphic devices are finally outlined.