Preparation and Performance Analysis of Ag/ZnO Humidity Sensor

Highly sensitive silver (Ag) modified zinc oxide (ZnO) humidity sensors were prepared by hydrothermal synthesis and the mechanism was studied. Experimental results show that Ag-modified ZnO can effectively enhance the performance of a humidity sensor. Large number of oxygen vacancies and many active sites are generated on the surface when molar ratio of Ag+ to Zn2+ is 1:100, which can accelerate the decomposition of water molecules on surface of the material, thereby improving the response of humidity sensor. Moreover, the linearity of ZnO humidity sensor is greatly improved by silver nanoparticles. Compared with previously reported ZnO-based humidity sensors, Ag/ZnO humidity sensors have a better response (151,700%), good linearity, low hysteresis (3%), and short response/recovery time (36/6 s). At the same time, it is found that the light had little effect on the performance of Ag/ZnO. Therefore, this kind of ZnO sensor with stable performance and excellent performance is expected to be used in the detection of relative humidity in conventional environments.

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Highly Sensitive Temperature and Humidity Sensor Based on Carbon Nanotube-Assisted Mismatched Single-Mode Fiber Structure

Micromachines ◽

10.3390/mi10080521 ◽

2019 ◽

Vol 10 (8) ◽

pp. 521 ◽

Cited By ~ 3

Author(s):

Yuan ◽

Qian ◽

Liu ◽

Wang ◽

Keyword(s):

Carbon Nanotube ◽

Humidity Sensor ◽

Single Mode ◽

Small Region ◽

Single Mode Fiber ◽

Fiber Structure ◽

Humidity Sensing ◽

Highly Sensitive ◽

Temperature And Humidity ◽

Stable Performance

Here we report on a miniaturized optical interferometer in one fiber based on two mismatched nodes. The all-fiber structure shows stable performance of temperature and humidity sensing. For temperature sensing in large ranges, from 40 to 100 °C, the sensor has a sensitivity of 0.24 dB/°C, and the adjusted R-squared value of fitting result reaches 0.99461 which shows a reliable sensing result. With carbon nanotubes coating the surface of the fiber, the temperature sensitivity is enhanced from 0.24561 to 1.65282 dB/°C in a small region, and the performance of humidity sensing becomes more linear and applicable. The adjusted R-squared value of the linear fitting line for humidity sensing shows a dramatic increase from 0.71731 to 0.92278 after carbon nanotube coating, and the humidity sensitivity presents 0.02571 nm/%RH.

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Low-Hysteresis and Fast Response Time Humidity Sensors Using Suspended Functionalized Carbon Nanotubes

Sensors ◽

10.3390/s19030680 ◽

2019 ◽

Vol 19 (3) ◽

pp. 680 ◽

Cited By ~ 9

Author(s):

Shivaram Arunachalam ◽

Ricardo Izquierdo ◽

Frederic Nabki

Keyword(s):

Carbon Nanotubes ◽

Response Time ◽

Humidity Sensor ◽

Fast Response ◽

Hysteresis Curve ◽

Humidity Sensors ◽

Fold Reduction ◽

Stable Performance ◽

Suspended Structure ◽

Temperature Surface

A humidity sensor using suspended carbon nanotubes (CNTs) was fabricated using a low-temperature surface micromachining process. The CNTs were functionalized with carboxylic acid groups that facilitated the interaction of water vapor with the CNTs. The humidity sensor showed a response time of 12 s and a recovery time of 47 s, along with superior hysteresis and stable performance. The hysteresis curve area of the suspended structure is 3.6, a 3.2-fold reduction in comparison to the non-suspended structure. A comparative study between suspended and non-suspended devices highlights the advantages of using a suspended architecture.

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Synthesized of Highly Sensitive Tin (IV)-Doped Zinc Oxide Humidity Sensor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1109.559 ◽

2015 ◽

Vol 1109 ◽

pp. 559-563

Author(s):

Ahmad Syakirin Ismail ◽

Mohd Firdaus Malek ◽

Muhammad Amir Ridhwan Abdullah ◽

Mohamad Hafiz Mamat ◽

M. Rusop

Keyword(s):

Zinc Oxide ◽

Recovery Time ◽

Humidity Sensor ◽

Sol Gel ◽

High Sensitivity ◽

Average Diameter ◽

Undoped Sample ◽

Immersion Method ◽

Response Recovery ◽

Highly Sensitive

High sensitivity Tin (IV) (Sn) - doped zinc oxide (ZnO) humidity sensor was deposited using sol-gel immersion method. The Sn-doped sample was deposited on glass substrate and undoped sample was also prepared to seem the improvement made through doping process. The analyses showed that the sensor’s morphology has become more porous and having lower average diameter of nanorods, high conductivity and higher response, recovery time, and sensitivity. The sensitivity of the sensor increased from 2 to 4 by doping with Sn.

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Development of La3+Doped CeO2Thick Film Humidity Sensors

Abstract and Applied Analysis ◽

10.1155/2014/297632 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Chunjie Wang ◽

Aihua Zhang ◽

Hamid Reza Karimi

Keyword(s):

Relative Humidity ◽

High Performance ◽

Humidity Sensor ◽

Humidity Sensors ◽

Response Recovery ◽

Relative Humidity Range ◽

Response And Recovery ◽

Sensitive Characteristics ◽

Humidity Range ◽

Maximum Humidity

The humidity sensitive characteristics of the sensor fabricated from 10 mol% La2O3doped CeO2nanopowders with particle size 17.26 nm synthesized via hydrothermal method were investigated at different frequencies. It was found that the sensor shows high humidity sensitivity, rapid response-recovery characteristics, and narrow hysteresis loop at 100 Hz in the relative humidity range from 11% to 95%. The impedance of the sensor decreases by about five orders of magnitude as relative humidity increases. The maximum humidity hysteresis is about 6% RH, and the response and recovery time is 12 and 13 s, respectively. These results indicate that the nanosized La2O3doped CeO2powder has potential application as high-performance humidity sensor.

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Performance of the highly sensitive humidity sensor constructed with nanofibrillated cellulose/graphene oxide/polydimethylsiloxane aerogel via freeze drying

RSC Advances ◽

10.1039/d0ra08193k ◽

2021 ◽

Vol 11 (3) ◽

pp. 1543-1552

Author(s):

Yutong Yang ◽

Guoting Su ◽

Qilin Li ◽

Zipiao Zhu ◽

Shaoran Liu ◽

...

Keyword(s):

Graphene Oxide ◽

Freeze Drying ◽

Humidity Sensor ◽

High Sensitivity ◽

Nanofibrillated Cellulose ◽

Rapid Response ◽

Response Recovery ◽

Highly Sensitive ◽

Recovery Behavior

This work presents a nanocellulose-based humidity sensor with high sensitivity, remarkable reproducibility and rapid response/recovery behavior fabricated via freeze drying.

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Effects of pH on High-Performance ZnO Resistive Humidity Sensors Using One-Step Synthesis

Sensors ◽

10.3390/s19235267 ◽

2019 ◽

Vol 19 (23) ◽

pp. 5267 ◽

Cited By ~ 2

Author(s):

Yu ◽

Zhang ◽

Keyword(s):

High Performance ◽

Oxygen Vacancies ◽

Humidity Sensor ◽

Ph Value ◽

Precursor Solution ◽

Hydroxyl Group ◽

Water Molecules ◽

Hydroxyl Groups ◽

Humidity Sensors ◽

One Step

In this paper, we prepared a high-performance zinc oxide (ZnO) humidity sensor in an alkaline environment using one-step hydrothermal method. Experiments showed that the pH value of the precursor solution affects the performance of ZnO humidity sensors. There are abundant hydroxyl group and oxygen vacancies on the surface of ZnO with a precursor pH value of 10. Abundant hydroxyl groups on the surface of ZnO can adsorb a large number of water molecules and rich oxygen vacancies can accelerate the decomposition of water molecules, thus increasing the number of conductive ions (H3O+) and further improving the performance of the sensor. So, such a ZnO humidity sensor exhibited high sensitivity (14,415), good linearity, small hysteresis (0.9%), fast response/recovery time (31/15 s) in the range from 11% to 95% relative humidity (RH). Moreover, the ZnO-2 humidity sensor has good repeatability and can be effectively used for a long time. This study provides a new idea for the development of low-cost, high-performance and reusable ZnO resistive humidity sensors.

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Humidity Sensors with Shielding Electrode Under Interdigitated Electrode

Sensors ◽

10.3390/s19030659 ◽

2019 ◽

Vol 19 (3) ◽

pp. 659 ◽

Cited By ~ 3

Author(s):

Hong Liu ◽

Qi Wang ◽

Wenjie Sheng ◽

Xubo Wang ◽

Kaidi Zhang ◽

...

Keyword(s):

Humidity Sensor ◽

High Sensitivity ◽

Fast Response ◽

Capacitive Sensors ◽

Humidity Sensors ◽

Interdigitated Electrode ◽

Response Recovery ◽

Chip Fabrication ◽

Good Agreement ◽

Capacitive Humidity Sensor

Recently, humidity sensors have been investigated extensively due to their broad applications in chip fabrication, health care, agriculture, amongst others. We propose a capacitive humidity sensor with a shielding electrode under the interdigitated electrode (SIDE) based on polyimide (PI). Thanks to the shielding electrode, this humidity sensor combines the high sensitivity of parallel plate capacitive sensors and the fast response of interdigitated electrode capacitive sensors. We use COMSOL Multiphysics to design and optimize the SIDE structure. The experimental data show very good agreement with the simulation. The sensitivity of the SIDE sensor is 0.0063% ± 0.0002% RH. Its response/recovery time is 20 s/22 s. The maximum capacitance drift under different relative humidity is 1.28% RH.

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Self-Assembled Polymer Thin Films Towards Nanoarchitectonics for Respiration Monitoring

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17458 ◽

2020 ◽

Vol 20 (5) ◽

pp. 2893-2901

Author(s):

Premkumar Jayaraman ◽

Chinnasamy Sengottaiyan ◽

Karthik Krishnan

Keyword(s):

Thin Films ◽

Morphological Analysis ◽

Humidity Sensor ◽

Polymer Thin Films ◽

Respiration Monitoring ◽

Response Recovery ◽

Human Respiration ◽

Highly Sensitive ◽

Transport Path ◽

Self Assembled

Manipulation of ionic transport in the self-assembled polymer thin films using nanoarchitectonics approach can open the door for the development of novel electronic devices with ultrafast operation and low-power consumption. Here, we demonstrate a highly sensitive and ultrafast responsive flexible humidity sensor for human respiration monitoring. Humidity sensing behavior of the polymerbased planar devices, in which a polyethylene oxide-phosphotungstic acid (PEO-PWA) thin film is placed between an opposing inert electrodes, have been investigated by optimizing the device configuration and PWA salt concentration in the PEO matrix. The ultrafast response (~50 ms) and recovery (~52 ms) of the humidity sensor enabled us to study the real-time human respiration monitoring. Using morphological analysis, it is proposed that the ultrafast response-recovery time for this sensor is ascribed to their self-assembled lamellar-like structures of the PEO-PWA matrix polymer, which provides long-range continuous proton transport path in the polymer interface.

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Fast and highly sensitive humidity sensors based on NaNbO3 nanofibers

RSC Advances ◽

10.1039/c5ra00205b ◽

2015 ◽

Vol 5 (26) ◽

pp. 20453-20458 ◽

Cited By ~ 24

Author(s):

Youdong Zhang ◽

Xumin Pan ◽

Zhao Wang ◽

Yongming Hu ◽

Xiaoyuan Zhou ◽

...

Keyword(s):

Room Temperature ◽

Humidity Sensor ◽

Temperature Response ◽

Electrospinning Process ◽

Humidity Sensors ◽

Highly Sensitive

A humidity sensor based on NaNbO3 nanofiber networks with fast, ultra-sensitive and selective room-temperature response was fabricated through electrospinning process.

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Nonporous Inorganic Nanoparticle-Based Humidity Sensor: Evaluation of Humidity Hysteresis and Response Time

Sensors ◽

10.3390/s20143858 ◽

2020 ◽

Vol 20 (14) ◽

pp. 3858

Author(s):

Shinya Kano ◽

Harutaka Mekaru

Keyword(s):

Response Time ◽

Humidity Sensor ◽

Silica Nanoparticle ◽

Fast Response ◽

Inorganic Nanoparticles ◽

Humidity Sensors ◽

Inorganic Nanoparticle ◽

Response Recovery ◽

Recovery Times ◽

Nanoparticle Film

Fast-response humidity sensors using nanomaterials are attractive and have been intensively studied. Among the various nanomaterials, nonporous inorganic nanoparticles are suitable for use in humidity sensitive films for sensors. Here, we focus on a nonporous inorganic nanoparticle film and investigate a humidity sensor using the film. Hysteresis error and a dynamic response to a change of humidity are fundamental specifications of humidity sensors. A humidity sensor using a 50 nm silica nanoparticle film shows a hysteresis error of 2% at 85% RH and a response/recovery time of 2.8/2.3 s in 30% RH to 70% RH. We also summarize response/recovery times and hysteresis errors of state-of-the-art humidity sensors. As compared to those of commercial sensors and porous nanoparticle-based sensors evaluated using saturated salt solutions, the fabricated sensor shows a comparative hysteresis error and shorter response time.

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