open access

https://hdl.handle.net/2115/93016

Highly Stable, Flexible Isfet pH Sensor Using Sorted Semiconducting SWNTs in Aqueous Solution

英語

pH sensors

2023-10-10

John Wiley & Sons

Advanced Materials Technologies

8(21)

2300842

Flexible sensors enable gathering of information from nonplanar surfaces, which facilitates huge data collection tasks. Monitoring of pH levels in industrial wastewater is one example. For this purpose, stable, reliable flexible pH sensors are required to monitor pH in pipes or containers. Carbon nanotube field-effect transistors (CNT-FETs) are attractive transducers for flexible sensors because of their multiple functionalities, such as good electrical properties and mechanical flexibility. However, semiconducting single-walled carbon nanotubes (s-SWNTs) must be separated from metallic SWNTs of high purity for channel materials to be used in CNT-FETs. Here, we developed a simple method to sort s-SWNTs in an aqueous system using only dispersion and centrifugation. This sorting method is much less expensive than other techniques, such as density gradient ultracentrifugation, agarose-gel chromatography, or selective sorting by conjugated polymers. These sorted s-SWNTs result in high-performance CNT-FETs with electrical hysteresis reduced to almost zero and improved bias stability. Importantly, this method demonstrates the importance of the solubility parameter between polymers and water for CNT-FET hysteresis. The resulting carbon nanotubes also have high uniformity of characteristics, making them valuable as transducers for flexible sensors. Furthermore, real-time pH monitoring using ion-sensitive, field-effect transistors (ISFETs) based on CNT-FET is demonstrated in a drainage pipe.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Asai, M., Honda, S., Isshiki, N., Takesue, M., Hiraishi, A., Yamada, M. and Takei, K. (2023), Highly Stable, Flexible ISFET pH Sensor Using Sorted Semiconducting SWNTs in Aqueous Solution. Adv. Mater. Technol., 8: 2300842, which has been published in final form at https://doi.org/10.1002/admt.202300842. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

2365-709X