Ion-Exchange-Driven Ternary Organic Neuromorphic Devices with High Efficiency and Stability

Organic neuromorphic platforms based on top-gate ionic-liquid architectures rely on precise electrochemical doping at low operating voltages; however, intrinsically unfavorable polymer-ion interfaces often lead to unstable doping, elevated operating voltages, and poor device-to-device uniformity. Herein, we present a solution-processed ternary organic blend system composed of organic semiconductors and a binary ionic-liquid system, in which spontaneous ion exchange within the active layer establishes a stabilized ionic environment and facilitates anion access into semicrystalline domains. In situ X-ray and Raman spectroscopy measurements reveal that this stabilized ionic matrix enables efficient anion penetration and electrochemical doping even under short gate pulses. The resultant ternary-blend devices operate under a low gate voltage (V_GS = -3.5 V) while effectively suppressing rapid de-doping after bias removal. Notably, the ternary organic blend system exhibits consistent and enhanced electrochemical doping behavior across semiconducting polymers with fundamentally different backbone chemistries, ranging from thiophene-based donor polymers to donor-acceptor conjugated systems. In particular, the devices exhibit remarkable electrical and neuromorphic performance, including long retention (∼25h), stable operation over ∼10³ sequential pulses, and reliable synaptic characteristics under various stimuli. This ternary strategy enables high-reliability organic neuromorphic systems, achieving 97.98% recognition accuracy in CNN-based MNIST classification.