McGhee_acsaelm.0c00660.pdf (3 MB)
Printed, fully metal oxide, capacitive humidity sensors using conductive indium tin oxide inks
journal contribution
posted on 2020-12-10, 14:54 authored by Jack McGhee, Jagdeep Sagu, Darren SoutheeDarren Southee, Peter S.A Evans, Upul Wijayantha-Kahagala-Gamage© In this research, fully metal oxide, capacitive humidity sensors for printed electronic applications have been designed and fabricated through the development of conductive indium tin oxide and dielectric aluminum oxide inks for the screen-printing process. Sensors were printed in a parallel plate configuration in 4 and 9 cm2 conductive plate areas. Typically, commercially available discrete humidity sensors have a sensitivity in the range of 0.2-0.5 pF/RH%, whereas the printed humidity sensors presented in this paper have sensitivities of 0.85-7.76 pF/RH% depending on the sensor size, allowing for customizable properties. Response times were measured using a weighted average and found to be 21.4 s on average and recovery times were 4.8 s on average. The sensing performance was highly linear (R2 > 0.97) for sensors of all sizes across the measured humidity range of 5-95%. Impedance spectroscopy was used to determine the sensing mechanism, and the mechanism was simulated and matched with experimental data. The sensing mechanism analysis shows that the sensing is primarily dictated by alumina at a lower relative humidity. The ITO contributes through increasing the ionic conductivity at a higher relative humidity, contributing to the high linearity of the sensor.
Funding
Sustainable Manufacturing of Transparent Conducting Oxide (TCO) Inks and Thin Films
Engineering and Physical Sciences Research Council
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School
- Design and Creative Arts
- Science
Department
- Chemistry
- Design
Published in
ACS Applied Electronic MaterialsVolume
2Issue
11Pages
3593 - 3600Publisher
American Chemical Society (ACS)Version
- VoR (Version of Record)
Publisher statement
This is an Open Access Article. It is published by American Chemical Society under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Acceptance date
2020-10-11Publication date
2020-10-22Copyright date
2020ISSN
2637-6113eISSN
2637-6113Publisher version
Language
- en
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Deposit date: 8 December 2020Usage metrics
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