A micro room temperature oxygen sensor based on LaF3 solid electrolyte thin film
ISSN: 0260-2288
Article publication date: 24 August 2023
Issue publication date: 21 November 2023
Abstract
Purpose
Detecting O2 gas in a confined space at room temperature is particularly important to monitor the work process of precision equipment. This study aims to propose a miniaturized, low-cost, mass-scale produced O2 sensor operating around 30°C.
Design/methodology/approach
The O2 sensor based on lanthanum fluoride (LaF3) solid electrolyte thin film was developed using MEMS technology. The principle of the sensor was a galvanic cell H2O, O2, Pt | LaF3 | Sn, SnF2 |, in which the Sn film was prepared by magnetron sputtering, and the LaF3 film was prepared by thermal resistance evaporation.
Findings
Through pretreatments, the sensor’s response signal to 40% oxygen concentration was enhanced from 1.9 mV to 46.0 mV at 30°C and 97.0% RH. Tests at temperatures from 30°C to 50°C and humidity from 32.4% RH to 97.0% RH indicated that the output electromotive force (EMF) has a linear relationship with the logarithm of the oxygen concentration. The sensitivity of the sensor increases with an increase in both humidity and temperature in the couple mode, and the EMF of the sensor follows well with the Nernst equation at different temperatures and humidity.
Practical implications
This research could be applied to monitor the oxygen concentration below 25% in confined spaces at room temperature safely without a power supply.
Originality/value
The relationship between temperature and humidity coupling and the response of the sensor was obtained. The nano-film material was integrated with the MEMS process. It is expected to be practically applied in the future.
Keywords
Acknowledgements
This work is supported by National Key R&D Program of China (2022YFB3206800), NSAF (Grant No. U1930205), Science and Technology Planning Project of Shenzhen (Grant No. JSGG20191129102808151), Fundamental Research Funds for the Central Universities (Grant No. xzd012019020), Key Research and Development Projects of Shaanxi Province (Grant No. 2019GY-121, 2020GY-137). The authors appreciate the support from International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies.
Citation
Tang, Y., Zhang, M., Chen, K., Nawaz, S.A., Wang, H., Wang, J. and Tian, X. (2023), "A micro room temperature oxygen sensor based on LaF3 solid electrolyte thin film", Sensor Review, Vol. 43 No. 5/6, pp. 318-331. https://doi.org/10.1108/SR-02-2021-0044
Publisher
:Emerald Publishing Limited
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