Dopamine‐Mediated Analog Control of Electrochromic Reactions Through Organic Electrochemical Transistor

The growing interest in bioinspired devices has led to a focus on bridging biological and electronic systems. Current bioelectronic devices predominantly rely on electrical signals and are unable to faithfully emulate the chemical signaling that plays a pivotal role in biological systems. To bridge this gap, we employ an organic electrochemical transistor (OECT) as the core of new platforms that integrates chemical sensing, analog computing, and electrochemical actuation in a single system. The OECT functions as a dopamine sensor. When a constant drain current is applied, dopamine oxidation at the gate electrode modulates both the drain voltage and the drain potential, as demonstrated by the measurements carried out with a reference electrode. These potential changes, usually exceeding 59 mV, are sufficient to significantly influence downstream electrochemical reactions. By fixing the drain current and gate voltage, the device enables tunable control over the electrochemical potential window. Actuation is demonstrated by electrically coupling the drain terminal to an electrochromic electrode, enabling direct and real‐time modulation of color in two different smart window materials: Prussian Blue and polyaniline. These results establish a versatile framework for chemical signal processing and actuation, enabling the next generation of adaptive bioelectronic interfaces that operate in chemical language.