Highly-Sensitive Textile Pressure Sensors Enabled by Suspended-Type All Carbon Nanotube Fiber Transistor Architecture

• Main Authors: Jae Sang Heo, Keon Woo Lee, Jun Ho Lee, Seung Beom Shin, Jeong Wan Jo, Yong Hoon Kim, Myung Gil Kim, Sung Kyu Park
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Micromachines
• Subjects: fiber transistors; pressure sensors; e-textile; wearable devices; active-matrix sensors
• Online Access: https://www.mdpi.com/2072-666X/11/12/1103

Among various wearable health-monitoring electronics, electronic textiles (e-textiles) have been considered as an appropriate alternative for a convenient self-diagnosis approach. However, for the realization of the wearable e-textiles capable of detecting subtle human physiological signals, the low-sensing performances still remain as a challenge. In this study, a fiber transistor-type ultra-sensitive pressure sensor (FTPS) with a new architecture that is thread-like suspended dry-spun carbon nanotube (CNT) fiber source (S)/drain (D) electrodes is proposed as the first proof of concept for the detection of very low-pressure stimuli. As a result, the pressure sensor shows an ultra-high sensitivity of ~3050 Pa⁻¹ and a response/recovery time of 258/114 ms in the very low-pressure range of <300 Pa as the fiber transistor was operated in the linear region (<i>V</i>_DS = −0.1 V). Also, it was observed that the pressure-sensing characteristics are highly dependent on the contact pressure between the top CNT fiber S/D electrodes and the single-walled carbon nanotubes (SWCNTs) channel layer due to the air-gap made by the suspended S/D electrode fibers on the channel layers of fiber transistors. Furthermore, due to their remarkable sensitivity in the low-pressure range, an acoustic wave that has a very tiny pressure could be detected using the FTPS.