Humidity Sensors on Flexible Substrate

2019 ◽  
pp. 347-364
Author(s):  
Ghenadii Korotcenkov
Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 148 ◽  
Author(s):  
Francisco J. Romero ◽  
Almudena Rivadeneyra ◽  
Markus Becherer ◽  
Diego P. Morales ◽  
Noel Rodríguez

In this paper, we present a simple, fast, and cost-effective method for the large-scale fabrication of high-sensitivity humidity sensors on flexible substrates. These sensors consist of a micro screen-printed capacitive structure upon which a sensitive layer is deposited. We studied two different structures and three different sensing materials by modifying the concentration of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) in a graphene oxide (GO) solution. The results show that the aggregation of the PEDOT:PSS to the GO can modify its electrical properties, boosting the performance of the capacitive sensors in terms of both resistive losses and sensitivity to relative humidity (RH) changes. Thus, in an area less than 30 mm2, the GO/PEDOT:PSS-based sensors can achieve a sensitivity much higher (1.22 nF/%RH at 1 kHz) than other similar sensors presented in the literature which, together with their good thermal stability, time response, and performance over bending, demonstrates that the manufacturing approach described in this work paves the way for the mass production of flexible humidity sensors in an inexpensive way.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaoyi Wang ◽  
Yang Deng ◽  
Xingru Chen ◽  
Peng Jiang ◽  
Yik Kin Cheung ◽  
...  

AbstractThe humidity sensor is an essential sensing node in medical diagnosis and industrial processing control. To date, most of the reported relative humidity sensors have a long response time of several seconds or even hundreds of seconds, which would limit their real application for certain critical areas with fast-varying signals. In this paper, we propose a flexible and low-cost humidity sensor using vertically aligned carbon nanotubes (VACNTs) as electrodes, a PDMS-Parylene C double layer as the flexible substrate, and graphene oxide as the sensing material. The humidity sensor has an ultrafast response of ~20 ms, which is more than two orders faster than most of the previously reported flexible humidity sensors. Moreover, the sensor has a high sensitivity (16.7 pF/% RH), low hysteresis (<0.44%), high repeatability (2.7%), good long-term stability, and outstanding flexibility. Benefiting from these advantages, especially the fast response, the device has been demonstrated in precise human respiration monitoring (fast breathing, normal breathing, deep breathing, asthma, choking, and apnea), noncontact electrical safety warning for bare hand and wet gloves, and noncontact pipe leakage detection. In addition, the facile fabrication of the flexible platform with the PDMS-Parylene C double layer can be easily integrated with multisensing functions such as pH sensing, ammonium ion sensing, and temperature sensing, all of which are useful for more pattern recognition of human activity.


PIERS Online ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Haipeng Lu ◽  
Jing Yang ◽  
Longjiang Deng

Author(s):  
Byoung-Joon Kim ◽  
Hae-A-Seul Shin ◽  
In-Suk Choi ◽  
Young-Chang Joo

Abstract The electrical resistance Cu film on flexible substrate was investigated in cyclic bending deformation. The electrical resistance of 1 µm thick Cu film on flexible substrate increased up to 120 % after 500,000 cycles in 1.1 % tensile bending strain. Crack and extrusion were observed due to the fatigue damage of metal film. Low bending strain did not cause any damage on metal film but higher bending strain resulted in severe electrical and mechanical damage. Thinner film showed higher fatigue resistance because of the better mechanical property of thin film. Cu film with NiCr under-layer showed poorer fatigue resistance in tensile bending mode. Ni capping layer did not improve the fatigue resistance of Cu film, but Al capping layer suppressed crack formation and lowered electrical resistance change. The NiCr under layer, Ni capping layer, and Al capping layer effect on electrical resistance change of Cu film was compared with Cu only sample.


2017 ◽  
Vol 9 (5) ◽  
pp. 05035-1-05035-6 ◽  
Author(s):  
G. I. Kopach ◽  
◽  
R. P. Mygushchenko ◽  
G. S. Khrypunov ◽  
A. I. Dobrozhan ◽  
...  

2020 ◽  
Vol 315 ◽  
pp. 112341
Author(s):  
Zhaojun Liu ◽  
Bian Tian ◽  
Xu Fan ◽  
Jiangjiang Liu ◽  
Zhongkai Zhang ◽  
...  

2017 ◽  
Vol 53 (32) ◽  
pp. 4465-4468 ◽  
Author(s):  
Yuan Gao ◽  
Pengtao Jing ◽  
Ning Yan ◽  
Michiel Hilbers ◽  
Hong Zhang ◽  
...  

Combined photoluminescence and impedance spectroscopy studies show that a europium-based metal–organic framework behaves as a highly effective and reliable humidity sensor, enabling dual-mode humidity detection.


1994 ◽  
Vol 22 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Andrew R.K. Ralston ◽  
Jeffrey A. Tobin ◽  
Sateesh S. Bajikar ◽  
Denice D. Denton

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