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

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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High-performance humidity sensors from Ni(SO4)0.3(OH)1.4 nanobelts

Nanoscale ◽

10.1039/c4nr00277f ◽

2014 ◽

Vol 6 (12) ◽

pp. 6521-6525 ◽

Cited By ~ 7

Author(s):

Ming Zhuo ◽

Yuejiao Chen ◽

Tao Fu ◽

Haonan Zhang ◽

Zhi Xu ◽

...

Keyword(s):

High Performance ◽

Humidity Sensor ◽

High Sensitivity ◽

Fast Response ◽

Humidity Sensors ◽

Term Stability ◽

Long Term Stability

Ni(SO4)0.3(OH)1.4 nanobelts are utilized in a humidity sensor by a facile method. The nanobelt based sensor shows a high sensitivity, fast response and long-term stability in the sensing process.

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Hydration States of Cholinium Phosphate-Type Ionic Liquids as a Function of Water Content

Australian Journal of Chemistry ◽

10.1071/ch18381 ◽

2019 ◽

Vol 72 (5) ◽

pp. 392 ◽

Cited By ~ 3

Author(s):

Yohsuke Nikawa ◽

Seiji Tsuzuki ◽

Hiroyuki Ohno ◽

Kyoko Fujita

Keyword(s):

Ionic Liquids ◽

Water Content ◽

Alkyl Chain ◽

Hydroxyl Group ◽

Water Molecules ◽

Hydroxyl Groups ◽

Ion Structure ◽

Activity Measurements ◽

Microscopic Interactions ◽

Dynamics Simulations

We investigated the hydration states of cholinium phosphate-type ionic liquids (ILs) in relation to ion structure, focusing on the influence of the hydroxyl group of the cation and the alkyl chain length of the anion. Water activity measurements provided information on the macroscopic hydration states of the hydrated ILs, while NMR measurements and molecular dynamics simulations clearly showed the microscopic interactions and coordination of the water molecules. The hydrogen bonding networks in these ILs were influenced by the anion structure and water content, and the mobility of water molecules was influenced by the number of hydroxyl groups in the cation and anion.

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Highly chemoresistive humidity sensing using poly(ionic liquid)s

Chemical Communications ◽

10.1039/c6cc04056j ◽

2016 ◽

Vol 52 (54) ◽

pp. 8417-8419 ◽

Cited By ~ 26

Author(s):

Lingling Wang ◽

Xiaochuan Duan ◽

Wuyuan Xie ◽

Qiuhong Li ◽

Taihong Wang

Keyword(s):

Ionic Liquid ◽

Relative Humidity ◽

High Performance ◽

Humidity Sensor ◽

High Sensitivity ◽

Fast Response ◽

Humidity Sensors ◽

Humidity Sensing ◽

Good Repeatability ◽

Poly Ionic Liquid

A novel resistance type humidity sensor was fabricated using poly(ionic liquid)s, which exhibited high sensitivity, fast response, small hysteresis and good repeatability at a relative humidity (RH) in the range of 11–98%, making poly(ionic liquid)s as promising sensing materials for high-performance humidity sensors.

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Humidity sensors based on graphene/SnOx/CF nanocomposites

Journal of Materials Chemistry C ◽

10.1039/c4tc00440j ◽

2014 ◽

Vol 2 (24) ◽

pp. 4861-4866 ◽

Cited By ~ 18

Author(s):

Tao Fu ◽

Jian Zhu ◽

Ming Zhuo ◽

Bingkun Guan ◽

Jidong Li ◽

...

Keyword(s):

High Performance ◽

Humidity Sensor ◽

Humidity Sensors

A high performance humidity sensor with the advantages of both graphene and SnOx/CFs.

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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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Towards clathrates. 2. The frozen states of hydration of tert-butanol

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2017-2074 ◽

2018 ◽

Vol 233 (1) ◽

pp. 41-49 ◽

Cited By ~ 3

Author(s):

Lukasz Dobrzycki

Keyword(s):

Single Crystal ◽

Crystalline Phase ◽

Ambient Pressure ◽

Water System ◽

Hydroxyl Group ◽

Molar Ratio ◽

Water Molecules ◽

Hydroxyl Groups ◽

Hydrogen Atoms ◽

Ir Laser

AbstractA new crystal structure oftert-butanol and water crystallizing as the decahydrate is reported. The crystallization of the mixture in the desired molar ratio was performed in a capillary placed directly on a goniometer of a single crystal diffractometer at 200 K and ambient pressure using focused IR laser radiation. The crystals were grown while the melting zone formed by the IR laser was moved along the capillary. Usually the crystallization process should be long enough (hours) in order to obtain a good quality single crystal. However, in the case oftert-butanol decahydrate, such a long process led to separation of the ice and alcohol. Only fast crystallization taking tens of seconds allowed crystallization of the desired crystalline phase. In the decahydratetert-butanol molecules are located in channels formed by water molecules. Hydroxyl groups are anchored to the water framework via hydrogen bonds. All water molecules in the structure have hydrogen atoms disordered equally over two sites; the hydroxyl group is likewise disordered. This effect is observed at both, 200 K and 100 K. Raman spectra recorded for the crystalline phase suggest dynamic disorder at higher temperature, converting to static at lowerT. The decahydrate oftert-butanol, together with already known itsdi- andhepta-hydrates, display similar features to those observed for series oftert-butylamine hydrates. The latter structures behave as frozen steps of amine hydration observed as crystal structures leading, at maximum dilution, to hexagonal ice. Hydrates oftert-butanol nicely follow this tendency completing the relationship found for thetert-butylamine: water system.

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High-performance humidity sensors based on electrospinning ZnFe2O4 nanotubes

RSC Advances ◽

10.1039/c5ra09903j ◽

2015 ◽

Vol 5 (84) ◽

pp. 68299-68304 ◽

Cited By ~ 8

Author(s):

Ming Zhuo ◽

Ting Yang ◽

Tao Fu ◽

Qiuhong Li

Keyword(s):

High Performance ◽

Humidity Sensor ◽

Hollow Structure ◽

Electrical Measurements ◽

Excellent Performance ◽

Humidity Sensors ◽

Humidity Sensing ◽

Electrospinning Method

In this paper, ZnFe2O4 nanotubes with hollow structure were synthesized by a simple electrospinning method. Humidity sensor was fabricated based on these nanotubes. The electrical measurements show excellent performance in humidity sensing.

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Preparation and Performance Analysis of Ag/ZnO Humidity Sensor

Sensors ◽

10.3390/s21030857 ◽

2021 ◽

Vol 21 (3) ◽

pp. 857

Author(s):

Peng Li ◽

Shuguo Yu ◽

Hongyan Zhang

Keyword(s):

Active Sites ◽

Humidity Sensor ◽

Molar Ratio ◽

Water Molecules ◽

Humidity Sensors ◽

Response Recovery ◽

Highly Sensitive ◽

Stable Performance ◽

And Performance ◽

Decomposition Of Water

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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Heterogeneous ice nucleation correlates with bulk-like interfacial water

Science Advances ◽

10.1126/sciadv.aat9825 ◽

2019 ◽

Vol 5 (4) ◽

pp. eaat9825 ◽

Cited By ~ 19

Author(s):

Shuwang Wu ◽

Zhiyuan He ◽

Jinger Zang ◽

Shenglin Jin ◽

Zuowei Wang ◽

...

Keyword(s):

Energy Barrier ◽

Bound Water ◽

Ice Nucleation ◽

Hydroxyl Group ◽

Water Molecules ◽

Hydroxyl Groups ◽

Interfacial Water ◽

New Strategy ◽

Group Density ◽

Heterogeneous Ice Nucleation

Establishing a direct correlation between interfacial water and heterogeneous ice nucleation (HIN) is essential for understanding the mechanism of ice nucleation. Here, we study the HIN efficiency on polyvinyl alcohol (PVA) surfaces with different densities of hydroxyl groups. We find that the HIN efficiency increases with the decreasing hydroxyl group density. By explicitly considering that interfacial water molecules of PVA films consist of “tightly bound water,” “bound water,” and “bulk-like water,” we reveal that bulk-like water can be correlated directly to the HIN efficiency of surfaces. As the density of hydroxyl groups decreases, bulk-like water molecules can rearrange themselves with a reduced energy barrier into ice due to the diminishing constraint by the hydroxyl groups on the PVA surface. Our study not only provides a new strategy for experimentally controlling the HIN efficiency but also gives another perspective in understanding the mechanism of ice nucleation.

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