Thermally‐Drawn Multi‐Electrode Fibers for Bipolar Electrochemistry and Magnified Electrochemical Imaging

Imaging systems using closed bipolar electrode (cBPE) arrays and electrochemiluminescence (ECL) have attracted great attention in recent years as a 2D imaging platform with high spatiotemporal resolution. However, the fabrication techniques for cBPE arrays involve complicated procedures. Therefore, a new fabrication scheme enabling the mass production of cBPE arrays with high precision, reproducibility, and yield, is desired. Here, the use of a versatile and scalable thermal drawing process as a novel fabrication method for fiber-based cBPEs with feature sizes down to micro-/nanoscales is proposed. First, a single-electrode fiber consisting of a carbon-based composite as the electrode material is produced by thermal drawing. The fundamental electrical properties of the single-electrode fiber are characterized, and its applicability to the cBPE-ECL system is demonstrated. A multielectrode fiber is fabricated by subjecting a bundle of 104 single-electrode fibers to thermal drawing. Its usability as a cBPE array for ECL imaging is confirmed with a functional rate of 99%. Further the multielectrode fiber, utilizing the principle of thermal drawing, for magnified electrochemical imaging is tapered. This work establishes a novel mass-production method for cBPE arrays, as well as a proof of concept for magnified electrochemical imaging using a thermally-drawn electrode array fiber.