scholarly journals Fabrication and Characterization of Flexible Capacitive Humidity Sensors Based on Graphene Oxide on Porous PTFE Substrates

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5118
Author(s):  
Zhenyu Wei ◽  
Jianqiu Huang ◽  
Wenhao Chen ◽  
Qingan Huang

Porous polytetrafluoroethylene (PTFE) is physically flexible, thermally and chemically stable, relatively inexpensive, and commercially available. It is attractive for various flexible sensors. This paper has studied flexible capacitive humidity sensors fabricated on porous PTFE substrates. Graphene oxide (GO) was used as a sensing material, both hydrophobic and hydrophilic porous PTFE as the substrates, and interdigitated electrodes on the PTFE substrates were screen-printed. SEM and Raman spectrum were utilized to characterize GO and PTFE. An ethanol soak process is developed to increase the yield of the humidity sensors based on hydrophobic porous PTFE substrates. Static and dynamic properties of these sensors are tested and analyzed. It demonstrates that the flexible capacitive humidity sensors fabricated on the ethanol-treated hydrophobic PTFE exhibit high sensitivity, small hysteresis, and fast response/recovery time.

2018 ◽  
Vol 6 (12) ◽  
pp. 5016-5024 ◽  
Author(s):  
Seo Yun Park ◽  
Yeon Hoo Kim ◽  
Seon Yong Lee ◽  
Woonbae Sohn ◽  
Jung Eun Lee ◽  
...  

Sensors based on 2D rGO/2D MoS2 van der Waals hybrid composites exhibited high sensitivity, extreme selectivity, fast response/recovery, and good reliability to humidity detection.


Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 659 ◽  
Author(s):  
Hong Liu ◽  
Qi Wang ◽  
Wenjie Sheng ◽  
Xubo Wang ◽  
Kaidi Zhang ◽  
...  

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.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Hai Ha ◽  
Nguyen Hoang Nam ◽  
Dang Duc Dung ◽  
Nguyen Huy Phuong ◽  
Phan Duy Thach ◽  
...  

We report the fabrication and characterization of surface acoustic wave (SAW) hydrogen sensors using palladium-graphene (Pd-Gr) nanocomposite as sensing material. The Pd-Gr nanocomposite as sensing layer was deposited onto SAW delay line sensor-based interdigitated electrodes (IDTs)/aluminum nitride (AlN)/silicon (Si) structure. The Pd-Gr nanocomposite was synthesized by a chemical route and deposited onto SAW sensors by air-brush spraying. The SAW H2 sensor using Pd-Gr nanocomposite as a sensing layer shows a frequency shift of 25 kHz in 0.5% H2 concentration at room temperature with good repeatability and stability. Moreover, the sensor showed good linearity and fast response/recovery within ten seconds with various H2 concentrations from 0.25 to 1%. The specific interaction between graphene and SAW transfer inside AlN/Si structures yields a high sensitivity and fast response/recovery of SAW H2 sensor based on Pd-Gr/AlN/Si structure.


2019 ◽  
Vol 287 ◽  
pp. 459-467 ◽  
Author(s):  
Francisco J. Romero ◽  
Almudena Rivadeneyra ◽  
Alfonso Salinas-Castillo ◽  
Akiko Ohata ◽  
Diego P. Morales ◽  
...  

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6521-6525 ◽  
Author(s):  
Ming Zhuo ◽  
Yuejiao Chen ◽  
Tao Fu ◽  
Haonan Zhang ◽  
Zhi Xu ◽  
...  

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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