Fig. 1. Initial calibration of five thin-film humidity sensors from different manufacturers before exposure to high and low humidity.
Fig. 2. Exposure of humidity sensors to high humidity (~95 %rh) in water chamber for four months.
Fig. 4. Increase of device reading values of humidity sensors after long-term exposure to high humidity as a function of reference relative humidity.
Fig. 5. Increase in device reading values of humidity sensors after long-term exposure to high humidity as a function of device price.
Fig. 6. Exposure of humidity sensors to low humidity (~10 %rh) in descant chamber for four months.
Fig. 8. Increase of device reading values of humidity sensors after long-term exposure to (a) high humidity followed by (b) low humidity as a function of reference relative humidity. Dashed rectangular boxes indicate 2 %rh variations from initial calibration.
Fig. 3. (a)-(e) Device reading values of humidity sensors (A-E, respectively) as a function of reference relative humidity before (black square) and after (blue circle) long-term exposure to high humidity.
Fig. 7. (a)-(d) Device reading values of humidity sensors (A-D, respectively) as a function of reference relative humidity before (black square) and after (blue circle) long-term exposure to high humidity, and after (red triangle) long-term exposure to low humidity.
References
- M. A. Najeeb, Z. Ahmad, and R. A. Shakoor, "Organic thin-film capacitive and resistive humidity sensors: A focus review," Adv. Mater. Interfaces, https://doi.org/10.1002/admi.201800969.
- H. Farahani, R.Wagiran, and M. N. Hamidon, "Humidity sensors principle, mechanism, and fabrication technologies: A comprehensive review," Sensors, Vol. 14, No. 5, pp. 7881-7939, 2014. https://doi.org/10.3390/s140507881
- Z. Chen and C. Lu, "Humidity sensors: A review of materials and mechanisms," Sens. Lett., Vol 3, No. 4, pp. 274-295, 2005. https://doi.org/10.1166/sl.2005.045
- Y. Sakai, Y. Sadaoka, and M. Matsuguchi, "Humidity sensors based on polymer thin films," Sens. Actuators B Chem., Vol. 35, No. 1-3, pp. 85-90, 1996. https://doi.org/10.1016/S0925-4005(96)02019-9
- W.-P. Chen, Z.-G. Zhao, X.-W. Liu, Z.-X. Zhang, and C.-G. Suo, "A capacitive humidity sensor based on multi-wall carbon nanotubes (MWCNTs)," Sensors, Vol. 9, No. 9, pp. 7431-7444, 2009. https://doi.org/10.3390/s90907431
- H. Bi, K. Yin, X. Xie, J. Ji, S. Wan, L. Sun, M. Terrones, and M.S. Dresselhaus, "Ultrahigh humidity sensitivity of graphene oxide," Sci. Rep., Vol 3, pp. 2714(1)-2714(7), 2013.
- S. Borini, R. White, D. Wei, M. Astley, S. Haque, E. Spigone, N. Harris, J. Kivioja, and T. Ryhanen, "Ultrafast graphene oxide humidity sensors," ACS Nano, Vol. 7, No. 12, pp. 11166-11173, 2013. https://doi.org/10.1021/nn404889b
- S.-W. Lee, B. I. Choi, J. C. Kim, S.-B. Woo, Y.-G. Kim, S. Kwon, J. Yoo, and Y.-S. Seo, "Sorption/desorption hysteresis of thin-film humidity sensors based on graphene oxide and its derivative," Sens. Actuators B Chem., Vol. 237, pp. 575-580, 2016. https://doi.org/10.1016/j.snb.2016.06.113
- E. U. Park, B. I. Choi, J. C. Kim, S.-B. Woo, Y.-G. Kim, Y. Choi, and S.-W. Lee. "Correlation between the sensitivity and the hysteresis of humidity sensors based on graphene oxides," Sens. Actuators B Chem., Vol. 258, pp. 255-262, 2018. https://doi.org/10.1016/j.snb.2017.11.104
- B. I. Choi, S.-W. Lee, S.-B. Woo, J. C. Kim, Y.-G. Kim, and S. G. Yang, "Evaluation of radiosonde humidity sensors at low temperature using ultralow-temperature humidity chamber," Adv. Sci. Res., Vol. 15, pp. 207-212, 2018. https://doi.org/10.5194/asr-15-207-2018
- K. E. Secrist and A. J. Nolte, "Humidity swelling/deswelling hysteresis in a polyelectrolyte multilayer film," Macromolecules, Vol. 44, No. 8, pp. 2859-2865, 2011. https://doi.org/10.1021/ma101983s
- S.-W. Lee and D. Lee, "Integrated study of water sorption/ desorption behavior of weak polyelectrolyte layer-by-layer films," Macromolecules, Vol. 46, No. 7, pp. 2793-2799, 2013. https://doi.org/10.1021/ma400076d