Choline Ionic Liquid for Long‐Term Stable Organic Electrochemical Transistors

A choline-based ionic liquid is introduced into organic electrochemical transistors(OECTs) to achieve enhanced performance and long-term stability, and these OECTs can be used for sensing biological signals such as electrocardiograms (ECGs) and electromyograms (EMGs) for up to 3 months. Spectroscopic analysis and electrochemical characterization focused on the ionic interactions between the choline-based ionic liquid and PEDOT:PSS, particularly the impact on device operation. Their strong ionic interactions result in enhanced OECT electrical performance, including 80 ns of response time, faster than state-of-the-art devices. Furthermore, 3D arrays and ultrathin OECTs attached to skin with consistent performance are demonstrated for substantial applicability and potential in research for mapping biological signals of cells or tissues, and integration with wireless systems, enabling remote medical services.