Fully Printed Organic Electrochemical Transistor–Based Biomimetic Neuron

Organic electrochemical transistors (OECTs) combine ionic-electronic coupling with low-voltage operation and biocompatibility, yet neuron-level circuit implementations remain scarce. Here, we demonstrate a fully printed biomimetic neuron using direct-ink-writing (DIW) OECTs that reproduces leaky integrate-and-fire (LIF) dynamics. The circuit employs cascaded p-type OECT inverters, a reset transistor, and capacitive elements to implement integration, leakage, threshold detection, and spike generation using a single device type. The underlying OECT exhibits synaptic plasticity features—paired-pulse facilitation (PPF), spike-duration-dependent plasticity (SDDP), and pulse-number-dependent gain—arising from reversible ion-driven doping in poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS). The fully printed architecture is scalable, reproducible across multiple devices, and compatible with flexible and biological systems, making it an ideal building block for large-area neuromorphic arrays.