Organic electrochemical transistor-based channel dimension-independent single-strand wearable sweat sensors

Autor: Chi-Hyeong Kim, Seong-Min Kim, Sanghyun Ju, Sang Yoon Park, Keumyoung Seo, Jiwoong Kim, Youngseok Kim, Taekyung Lim, Myung-Han Yoon, Chang Su Yeo
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: NPG Asia Materials, Vol 10, Iss 11, Pp 1086-1095 (2018)
ISSN: 1884-4057
1884-4049
Popis: Despite the great potential of polymer microfibers in human-friendly wearable electronics, most previous polymeric electronics have been limited to thin-film-based devices due to practical difficulties in fabricating microfibrillar devices, as well as defining the active channel dimensions in a reproducible manner. Herein, we report on conducting polymer microfiber-based organic electrochemical transistors (OECTs) and their application in single-strand fiber-type wearable ion concentration sensors. We developed a simple wet-spinning process to form very conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) microfibers using aqueous sulfuric acid solutions and carefully examined their electrical/electrochemical properties. In conjunction with fabricating substrate-free PEDOT:PSS microfiber-based OECT devices, the proposed novel characterization method demonstrated that the current variation ratio can be a reliable method for evaluating the device performance for sensing ion concentrations, regardless of the actual channel dimensions. Finally, we developed single-strand fiber-type skin-mountable OECTs by introducing a source-gate hybrid electrode and demonstrated that the resultant microfiber sensors can perform real-time repetitive measurements of the ion concentration in human sweat. A wearable device that analyses sweat and could help athletes optimize their intake of fluids and electrolytes has been developed by researchers in South Korea. Wearable electronics provide a way to monitor the body around the clock, and even deliver simple healthcare solutions. Such devices need to be light, robust, and flexible enough to adapt to the wearer’s movement. Sanghyun Ju from Kyonggi University in Suwon, Myung-Han Yoon from Gwangju Institute of Science and Technology and their colleagues have made a wearable device that can measure the ion concentration in human sweat. Previous materials used in such devices required a substrate, which limited their mechanical flexibility. Instead, Ju, Yoon and the team created highly conductive microfibers, which they used to fabricate electrochemical transistors. The current through the transistor varied with ion concentration, enabling real-time measurements. In textile electronics, micro to millimeter-scaled misalignment is commonly occurred during the high-throughput and bulk-scaled textile manufacturing process, thus the exact performance control of the fiber-based active devices is very difficult in low-cost wearable electronics. In this research, we developed novel single-strand organic electrochemical transistors and proposed dimension-independent characterization method (i.e., the current variation ratio in variation of logarithmic concentration of electrolyte) for ion concentration sensing. Furthermore, we demonstrated the pseudo two-terminal transistor operation by incorporating electrochemical gate electrode onto the surface of the source electrode, leading to single-strand fiber device platform.
Databáze: OpenAIRE
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