Stable Organic Electrochemical Neurons

Recent progress in the design and synthesis of both p-type and n-type organic mixed ionic-electronic conductors (OMIECs) has led to the creation of power-efficient devices for diverse applications, including sensors, nervetronics, neural interfaces, and artificial synapses. A cutting-edge addition to the bioelectronic toolkit is the organic electrochemical neuron (OECN) with ion-modulated spiking, facilitating the development of event-based sensors capable of local sensing, signal processing, and stimulation/actuation. However, the current technology encounters stability challenges, primarily stemming from the degradation of the p-type organic electrochemical transistor (OECT) characteristics. Therefore, achieving stable p-type OMIECs is deemed essential for unlocking the full potential of high-performance OECNs. Here, we leverage the inherent stability of rigid ladder polymers, which can sustain a high degree of electrochemical doping. This intrinsic property results in exceptional operational stability, high charge carrier mobility, and large volumetric capacitance. By integrating both n-type and p-type ladder polymers with an engineered backbone to ensure efficient charge transport, we present integrate-and-fire OECNs exhibiting biologically relevant firing frequencies and unparalleled stability. Our findings represent a significant leap forward in OECN technology, addressing previous stability limitations and promising novel opportunities for the advancement of in-sensor computing and the broader field of bioelectronics.