Next Article in Journal
Electrochemical Hybrid Methods and Sensors for Antioxidant/Oxidant Activity Monitoring and Their Use as a Diagnostic Tool of Oxidative Stress: Future Perspectives and Challenges
Previous Article in Journal
Identification of Plastic Type and Surface Roughness of Film-Type Plastics in Water Using Kramers–Kronig Analysis
Open AccessArticle

RH Sensing by Means of TiO2 Nanoparticles: A Comparison among Different Sensing Techniques Based on Modeling and Chemical/Physical Interpretation

Department of Information Engineering and Mathematical Sciences, University of Siena, 53100 Siena, Italy
*
Author to whom correspondence should be addressed.
Chemosensors 2020, 8(4), 89; https://doi.org/10.3390/chemosensors8040089
Received: 30 August 2020 / Revised: 18 September 2020 / Accepted: 22 September 2020 / Published: 25 September 2020
(This article belongs to the Section Analytical Method and Apparatus)
TiO2 nanoparticles coating has been proven to be an extremely performing sensing material for relative humidity (RH) measurements. The chemical activity of TiO2 toward water vapor adsorption and the very large surface to volume ratio typical of nanostructures are ideal characteristics for the development of RH fast and sensitive sensors. Different sensor technologies can be used in conjunction with this material to realize devices with satisfactory performance. In this paper, the authors aim to describe and discuss the main different possible choices and highlight the advantages and disadvantages, and linking them both to the underlying mechanism of water adsorption on the TiO2 sensing layer and to the modification of the electrical behavior due to the water adsorption. In particular, the authors start from results obtained by depositing TiO2 nanoparticles on a novel MEMS microbalance operating at low frequency, which allows to sense only the adsorbed water mass, and they exploit the sensor output to obtain a dynamic model of the water adsorption. They also link these results to those obtained with a Quartz Crystal Microbalance (QCM) functionalized with the same material operating at 10 MHz as a part of an oscillator. Finally, they establish a link with the results obtained by an RH impedance sensor, which exploits the same active material and the same deposition technique. With this sensor technology, the conductive and electrical behavior of the sensing and adsorbed films play a role. The whole work tries to unravel the different phenomena that contribute to the response of RH sensors not only based on TiO2 nanoparticles but also, more generally, based on nanostructured metal oxide materials. View Full-Text
Keywords: TiO2 humidity sensor; TiO2 nanoparticles; water adsorption TiO2 humidity sensor; TiO2 nanoparticles; water adsorption
Show Figures

Figure 1

MDPI and ACS Style

Cappelli, I.; Fort, A.; Lo Grasso, A.; Panzardi, E.; Mugnaini, M.; Vignoli, V. RH Sensing by Means of TiO2 Nanoparticles: A Comparison among Different Sensing Techniques Based on Modeling and Chemical/Physical Interpretation. Chemosensors 2020, 8, 89.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop