Humidity-Sensing Properties of a BiOCl-Coated Quartz Crystal Microbalance

Chen, Qiao; Feng, Ningbo; Huang, Xianhe; Yao, Yao; Jin, Yang; Pan, Wei; Liu, D.

doi:10.1021/acsomega.0c01946

Cited by 27 publications

(9 citation statements)

References 69 publications

(95 reference statements)

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“…They found that a thinner graphene oxide film provides a shorter response time and smaller sensitivity (Δ f per %RH), attributed to the mass loads of adsorbed water molecules. Chen et al recently reported a QCM-based humidity sensor for respiratory monitoring under the nose [ 114 ]. They used a bismuth oxychloride film having a hydrophilic surface as a humidity-sensitive layer.…”

Section: Types Of Fast-response Humidity Sensormentioning

confidence: 99%

Respiratory Monitoring by Ultrafast Humidity Sensors with Nanomaterials: A Review

Kano

Jarulertwathana

Mohd-Noor

et al. 2022

Sensors

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Respiratory monitoring is a fundamental method to understand the physiological and psychological relationships between respiration and the human body. In this review, we overview recent developments on ultrafast humidity sensors with functional nanomaterials for monitoring human respiration. Key advances in design and materials have resulted in humidity sensors with response and recovery times reaching 8 ms. In addition, these sensors are particularly beneficial for respiratory monitoring by being portable and noninvasive. We systematically classify the reported sensors according to four types of output signals: impedance, light, frequency, and voltage. Design strategies for preparing ultrafast humidity sensors using nanomaterials are discussed with regard to physical parameters such as the nanomaterial film thickness, porosity, and hydrophilicity. We also summarize other applications that require ultrafast humidity sensors for physiological studies. This review provides key guidelines and directions for preparing and applying such sensors in practical applications.

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Section: Types Of Fast-response Humidity Sensormentioning

confidence: 99%

Respiratory Monitoring by Ultrafast Humidity Sensors with Nanomaterials: A Review

Kano

Jarulertwathana

Mohd-Noor

et al. 2022

Sensors

View full text Add to dashboard Cite

show abstract

“…In the past few decades, acoustic transducers including bulk acoustic wave (BAW) transducers, capacitive micromechanical ultrasonic transducers (CMUT), film bulk acoustic resonator (FBAR) transducers, and surface acoustic wave (SAW) transducers have been extensively developed in the field of gas and humidity sensing [ 8 , 9 ]. In particular, quartz crystal microbalance (QCM), as a typical BAW transducer, is a more desirable humidity transducer due to its ability to detect high sensitivity on the nanogram scale, simple structure, strong material selectivity, low cost, high interference immunity, and ability to withstand harsh environments [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Impedance Analysis of Chitin Nanofibers Integrated Bulk Acoustic Wave Humidity Sensor with Asymmetric Electrode Configuration

et al. 2022

Self Cite

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This paper fabricated a high-performance chitin nanofibers (ChNFs)-integrated bulk acoustic wave (BAW) humidity sensor with an asymmetric electrode configuration. The ChNFs were successfully prepared from crab shells and used as moisture-sensitive materials to compare the performance of quartz crystal microbalance (QCM) humidity sensors with symmetric and asymmetric electrode structures. The QCM humidity sensor with a smaller electrode area exhibited high sensitivity of 58.84 Hz/%RH, competitive response/recovery time of 30/3.5 s, and low humidity hysteresis of 2.5% RH. However, it is necessary to choose a suitable electrode diameter to balance the stability and sensitivity because the impedance analysis result showed that the reduction of the electrode diameter leads to a sharp decrease in the Q value (stability). Next, the possible humidity-sensitive mechanism of the ChNFs-integrated asymmetric n-m electrode QCM humidity sensor was discussed in detail. Finally, the reasons for the highest sensitivity of the asymmetric n-m electrode QCM humidity sensors having a smaller electrode diameter were analyzed in detail in terms of both mass sensitivity and fringing field effect. This work not only demonstrates that the chitin nanofiber is an excellent potential material for moisture detection, but also provides a new perspective for designing high-performance QCM humidity sensors.

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“…In this regard, there have been advances toward fabricating humidity sensors that are capable of detecting humidity levels in exhaled breath. Typically, sensing is achieved by measuring with various transducing methods, including capacitance, 7 , 8 resistance, 9 , 10 absorbance, 11 − 13 surface acoustic waves, 14 − 17 and adsorption on quartz crystal microbalance, 18 − 21 and by devices such as a field effect transistor. 22 , 23 A variety of materials including conducting polymers, metal oxides, noble metal nanoparticles, carbon nanotubes, and graphene oxide have been investigated for their humidity-sensing capabilities.…”

Section: Introductionmentioning

confidence: 99%

Toward Continuous Breath Monitoring on a Mobile Phone Using a Frugal Conducting Cloth-Based Smart Mask

et al. 2022

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A frugal humidity sensor that can detect changes in the humidity of exhaled breath of individuals has been fabricated. The sensor comprises a humiditysensitive conducting polymer that is in situ formed on a cloth that acts as a substrate. Interdigitated silver electrodes were screen-printed on the modified cloth, and conducting threads connected the electrodes to the measurement circuit. The sensor's response to changing humidity was measured as a voltage drop across the sensor using a microcontroller. The sensor was capable of discerning between fast, normal, and slow breathing based on the response time. A response time of ∼1.3 s was observed for fast breathing. An Android-based mobile application was designed to collect sensor data via Bluetooth for analysis. A time series classification algorithm was implemented to analyze patterns in breathing. The sensor was later stitched onto a face mask, transforming it into a smart mask that can monitor changes in the breathing pattern at work, play, and sleep.

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Humidity-Sensing Properties of a BiOCl-Coated Quartz Crystal Microbalance

Cited by 27 publications

References 69 publications

Respiratory Monitoring by Ultrafast Humidity Sensors with Nanomaterials: A Review

Respiratory Monitoring by Ultrafast Humidity Sensors with Nanomaterials: A Review

Impedance Analysis of Chitin Nanofibers Integrated Bulk Acoustic Wave Humidity Sensor with Asymmetric Electrode Configuration

Toward Continuous Breath Monitoring on a Mobile Phone Using a Frugal Conducting Cloth-Based Smart Mask

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