scholarly journals Porous Nanostructured Gadolinium Aluminate for High-Sensitivity Humidity Sensors

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7102
Author(s):  
Corneliu Doroftei ◽  
Liviu Leontie
Keyword(s):  
Relative Humidity ◽  
Significant Influence ◽  
Humidity Sensor ◽  
Sol Gel ◽  
High Sensitivity ◽  
Combustion Method ◽  
Humidity Sensors ◽  
Oxide Compound ◽  
P Type ◽  
Highly Porous

This paper presents the synthesis of gadolinium aluminate (GdAlO3), an oxide compound with a perovskite structure, for applications as a capacitive and/or resistive humidity sensor. Gadolinium aluminate was synthesized by the sol-gel self-combustion method. This method allowed us to obtain a highly porous structure in which open pores prevail, a structure favorable to humidity sensors. Most of the materials studied as capacitive/resistive humidity sensors have significant sensitivities only with respect to one of these types of sensors. In the case of the studied gadolinium aluminate with p-type electric conductivity, the relative humidity of the air has a significant influence on both capacitive and resistive types of electric humidity sensors. The capacity increases about 10,000 times, and the resistance decreases about 8000 times as the relative humidity increases from 0 to 98%. The investigated gadolinium aluminate can be used successfully to obtain high-sensitivity capacitive and/or resistive humidity sensors.

Highly chemoresistive humidity sensing using poly(ionic liquid)s

2016 ◽  
Vol 52 (54) ◽  
pp. 8417-8419 ◽  
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.

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

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6521-6525 ◽  
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.

A low cost relative humidity sensor fabricated by coating optical fused fiber coupler with sol-gel material

2008 ◽  
Author(s):  
Fufei Pang ◽  
Ping Xu ◽  
Min Wang ◽  
Xianglong Zeng ◽  
Zhenyi Chen ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Humidity Sensor ◽  
Low Cost ◽  
Sol Gel ◽  
Fiber Coupler ◽  
Relative Humidity Sensor

scholarly journals Relative Humidity Sensors Based on Microfiber Knot Resonators—A Review

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5196 ◽  
Author(s):  
Young-Geun Han
Keyword(s):  
Relative Humidity ◽  
High Sensitivity ◽  
Physical Parameters ◽  
Humidity Sensors ◽  
Coating Materials ◽  
High Q ◽  
Sensing Applications ◽  
Compact Size ◽  
The Many ◽  
Humidity Sensitivity

Recent research and development progress of relative humidity sensors using microfiber knot resonators (MKRs) are reviewed by considering the physical parameters of the MKR and coating materials sensitive to improve the relative humidity sensitivity. The fabrication method of the MKR based on silica or polymer is briefly described. The many advantages of the MKR such as strong evanescent field, a high Q-factor, compact size, and high sensitivity can provide a great diversity of sensing applications. The relative humidity sensitivity of the MKR is enhanced by concerning the physical parameters of the MKR, including the waist or knot diameter, sensitive materials, and Vernier effect. Many techniques for depositing the sensitive materials on the MKR surface are discussed. The adsorption effects of water vapor molecules on variations in the resonant wavelength and the transmission output of the MKR are described regarding the materials sensitive to relative humidity. The sensing performance of the MKR-based relative humidity sensors is discussed, including sensitivity, resolution, and response time.

scholarly journals Discriminable Sensing Response Behavior to Homogeneous Gases Based on n-ZnO/p-NiO Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 785 ◽  
Author(s):  
Wen-Dong Zhou ◽  
Davoud Dastan ◽  
Jing Li ◽  
Xi-Tao Yin ◽  
Qi Wang
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Sol Gel ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
P Type ◽  
Type Response ◽  
Properties Of Composites

Metal oxide semiconductor (MOS) gas sensors have the advantages of high sensitivity, short response-recovery time and long-term stability. However, the shortcoming of poor discriminability of homogeneous gases limits their applications in gas sensors. It is well-known that the MOS materials have similar gas sensing responses to homogeneous gases such as CO and H2, so it is difficult for these gas sensors to distinguish the two gases. In this paper, simple sol–gel method was employed to obtain the ZnO–xNiO composites. Gas sensing performance results illustrated that the gas sensing properties of composites with x > 0.425 showed a p-type response to both CO and H2, while the gas sensing properties of composites with x < 0.425 showed an n-type response to both CO and H2. However, it was interesting that ZnO–0.425NiO showed a p-type response to CO but an discriminable response (n-type) to H2, which indicated that modulating the p-type or n-type semiconductor concentration in p-n composites could be an effective method with which to improve the discriminability of this type of gas sensor regarding CO and H2. The phenomenon of the special gas sensing behavior of ZnO–0.425NiO was explained based on the experimental observations and a range of characterization techniques, including XRD, HRTEM and XPS, in detail.

scholarly journals Polymer Based Whispering Gallery Mode Humidity Sensor

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2383 ◽  
Author(s):  
Ann Petermann ◽  
Thomas Hildebrandt ◽  
Uwe Morgner ◽  
Bernhard Roth ◽  
Merve Meinhardt-Wollweber
Keyword(s):  
Relative Humidity ◽  
Humidity Sensor ◽  
Real Life ◽  
High Sensitivity ◽  
Whispering Gallery Mode ◽  
Whispering Gallery ◽  
Humidity Measurements ◽  
Wgm Resonators

Whispering gallery mode (WGM) resonators are versatile high sensitivity sensors, but applications regularly suffer from elaborate and expensive manufacturing and read-out. We have realized a simple and inexpensive concept for an all-polymer WGM sensor. Here, we evaluate its performance for relative humidity measurements demonstrating a sensitivity of 47 pm/% RH. Our results show the sensor concepts’ promising potential for use in real-life applications and environments.

Sol‐Gel Processing and Characterization of Silica Thin Films for on Chip Humidity Sensors

1996 ◽  
Vol 446 ◽  
Author(s):  
J.R. Kokan ◽  
R.A. Gerhardt
Keyword(s):  
Thin Films ◽  
Colloidal Silica ◽  
Sol Gel ◽  
High Sensitivity ◽  
Silica Thin Films ◽  
Highly Sensitive ◽  
On Chip ◽  
Gel Processing ◽  
Highly Porous

AbstractSilica thin films have been processed via a colloidal sol‐gel method which involves the hydrolyzing of potassium silicate and colloidal silica sol using formamide[l]. The resulting films are highly porous. The processing leaves residual potassium and sodium in the films which can then be removed through leaching in water. The dielectric properties of films which have been leached for twenty minutes are nearly insensitive to humidity. However, partially leached films, or films which have been doped with LiCl, KC1, or NaCl, are highly sensitive to humidity changes. The range of humidities over which these films have high sensitivity can be modified by changing the dopant type or varying the doping level. Films can be made to sense humidities ranging from 20% to 80% reproducibly. These films are ideal for microelectronic applications because they can be processed via dipping as well as spin coating and can also be easily etched.

scholarly journals Humidity-Insensitive NO2 Sensors Based on SnO2/rGO Composites

2021 ◽  
Vol 9 ◽  
Author(s):  
Yingyi Wang ◽  
Lin Liu ◽  
Fuqin Sun ◽  
Tie Li ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Gas Sensor ◽  
Chemical Engineering ◽  
Tin Dioxide ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Reduced Graphene ◽  
Real World Applications ◽  
High Level ◽  
P Type

This study reported a novel humidity-insensitive nitrogen dioxide (NO2) gas sensor based on tin dioxide (SnO2)/reduced graphene oxide (rGO) composites through the sol-gel method. The sensor demonstrated ppb-level NO2 detection in p-type sensing behaviors (13.6% response to 750 ppb). Because of the synergistic effect on SnO2/rGO p-n heterojunction, the sensing performance was greatly enhanced compared to that of bare rGO. The limit of detection of sensors was as low as 6.7 ppb under dry air. Moreover, benefited from the formed superhydrophobic structure of the SnO2/rGO composites (contact angle: 149.0°), the humidity showed a negligible influence on the dynamic response (Sg) of the sensor to different concentration of NO2 when increasing the relative humidity (RH) from 0 to 70% at 116°C. The relative conductivity of the sensor to 83% relative humidity was 0.11%. In addition, the response ratio (Sg/SRH) between 750 ppb NO2 and 83% RH was 649.0, indicating the negligible impaction of high-level ambient humidity on the sensor. The as-fabricated humidity-insensitive gas sensor can promise NO2 detection in real-world applications such as safety alarm, chemical engineering, and so on.

Piezotronics modulates high sensitivity relative humidity sensor based on single tellurium microwire

2019 ◽  
Vol 34 (7) ◽  
pp. 075011 ◽  
Author(s):  
Jinzong Kou ◽  
Aifang Yu ◽  
Yudong Liu ◽  
Mengmeng Jia ◽  
Junmeng Guo ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Humidity Sensor ◽  
High Sensitivity ◽  
Relative Humidity Sensor
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