Sensing performance of Nanocrystalline Graphite Based Humidity Sensors

Ting Yang Ling, Suan Hui Pu, Sam Fishlock, Yisong Han, Jamie Reynolds, John McBride, Harold Chong

Research output: Contribution to journalArticle

Abstract

Environmental sensors play a crucial role in a wide range of applications. Among them, humidity sensors that are stable and operational in harsh environments are incredibly important for process control and monitoring. Nanocrystalline graphite (NCG) is a type of carbon-based thin film material. Previous work has shown that NCG has excellent mechanical properties and is able to withstand high radiation doses. The granular structure of the NCG film makes it a good candidate for humidity sensing as the film consists of conductive graphitic grains with a high density of sp 2 bonds and amorphous grain boundaries with high resistivity, and adsorption of water molecule onto the film forms conductive pathways between grains through the Grotthuss mechanism which lowers the resistance of the film by a measurable amount. Here, we report for the first time a working humidity sensor with linear response, fabricated using NCG as the sensing material for harsh, real-world environments, which include exposure to weak acids via rainfall, UV radiation, mechanical wear, and high-humidity environments. The calculated sensitivity of the best-fabricated sensor is S = 0.0334 %, with a maximum resistance change of -4.4kΩ , over the range of 15% RH to 85% RH. The response time of the sensor is 20 ms with the current measurement setup. The baseline resistance value of the sensor at 15% RH is 210 kΩ. The sensor has the potential to be used as a humidity sensor for harsh environments due to the chemical, thermal, and mechanical stability of the NCG film.

LanguageEnglish
Article number8668501
Pages5421-5428
Number of pages8
JournalIEEE Sensors Journal
Volume19
Issue number14
Early online date31 Mar 2019
DOIs
Publication statusPublished - 15 Jul 2019

Fingerprint

Humidity sensors
humidity
Graphite
graphite
sensors
Sensors
Atmospheric humidity
Mechanical stability
Process monitoring
Chemical stability
Electric current measurement
Ultraviolet radiation
Dosimetry
Process control
Rain
Grain boundaries
Thermodynamic stability
Wear of materials
radiation
Adsorption

Keywords

  • Humidity , Mechanical sensors , Graphite , Graphene , Chemical sensors , Resistance
  • Nanocrystalline graphite
  • humidity sensors
  • PECVD
  • harsh environment

Cite this

Ling, T. Y., Pu, S. H., Fishlock, S., Han, Y., Reynolds, J., McBride, J., & Chong, H. (2019). Sensing performance of Nanocrystalline Graphite Based Humidity Sensors. IEEE Sensors Journal, 19(14), 5421-5428. [8668501]. https://doi.org/10.1109/JSEN.2019.2905719
Ling, Ting Yang ; Pu, Suan Hui ; Fishlock, Sam ; Han, Yisong ; Reynolds, Jamie ; McBride, John ; Chong, Harold. / Sensing performance of Nanocrystalline Graphite Based Humidity Sensors. In: IEEE Sensors Journal. 2019 ; Vol. 19, No. 14. pp. 5421-5428.
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Ling, TY, Pu, SH, Fishlock, S, Han, Y, Reynolds, J, McBride, J & Chong, H 2019, 'Sensing performance of Nanocrystalline Graphite Based Humidity Sensors', IEEE Sensors Journal, vol. 19, no. 14, 8668501, pp. 5421-5428. https://doi.org/10.1109/JSEN.2019.2905719

Sensing performance of Nanocrystalline Graphite Based Humidity Sensors. / Ling, Ting Yang; Pu, Suan Hui; Fishlock, Sam; Han, Yisong; Reynolds, Jamie; McBride, John; Chong, Harold.

In: IEEE Sensors Journal, Vol. 19, No. 14, 8668501, 15.07.2019, p. 5421-5428.

Research output: Contribution to journalArticle

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