scholarly journals PANI/MWCNT based humidity sensor

2019 ◽  
Vol 15 (33) ◽  
pp. 111-121
Author(s):  
Hammad R. Humud

Polyaniline Multi wall Carbon nanotube (PANI/MWCNTs) nanocomposite thin films have been prepared by Plasma jet polymerization at low frequency on glass substrate with preliminary deposited aluminum electrodes to form Al/PANI-MWCNT/Al surface-type capacitive humidity sensors, the gap between the electrodes about 50 μm and the MWCNTs weight concentration varied between 0, 1, 2, 3, 4%. The diameter of the MWCNTs was in the range of 8-15 nm and the length 10-55 μm. The capacitance-humidity relationships of the sensors were investigated at humidity levels from 35 to 90% RH. The electrical properties showed that the capacity increased with increasing relative humidity, and that the sensitivity of the sensor increases with the increase of the additive (MWCNTs); while each of the response time and the recovery time increasing with concentration. The change in MWCNTs concentration leads to a change in the energy gap as well as the initial capacity. The capacitance increases linearly with the relative humidity at MWCNTs concentration of 3% for thus the possibility of manufacturing humidity sensor with good specifications at this concentration.

2016 ◽  
Vol 52 (54) ◽  
pp. 8417-8419 ◽  
Author(s):  
Lingling Wang ◽  
Xiaochuan Duan ◽  
Wuyuan Xie ◽  
Qiuhong Li ◽  
Taihong Wang

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.


Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7102
Author(s):  
Corneliu Doroftei ◽  
Liviu Leontie

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chunjie Wang ◽  
Aihua Zhang ◽  
Hamid Reza Karimi

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.


2020 ◽  
Vol 6 (10) ◽  
pp. 244-252
Author(s):  
M. Matbabayev

This paper discusses the main characteristics of atmospheric air, the selected closed object on which the relative humidity depends to a certain extent, as well as a laboratory installation for studying the principle of constructing an optoelectronic sensor for measuring relative humidity. A description and diagram of the air humidity sensor, a block diagram of the installation for continuous monitoring of air humidity in the controlled object, a device for calibrating humidity sensors, and an algorithm for calibrating humidity sensors are given.


2006 ◽  
Vol 51 ◽  
pp. 197-200
Author(s):  
S. Krutovertsev ◽  
A. Tarasova ◽  
L. Krutovertseva ◽  
A. Zorin ◽  
O. Ivanova

Constraction and characteristics of sorption polymeric relative humidity sensors, sorption SiOx microhumidity sensors, and condensation type (dew point) sensors are compared. The characteristics of the sensors are examined in dew point range from -80 to +20oC. An integrated multifunctional humidity sensor, for measurements in wide humidity range at different conditions is developed. The sensors are intended for use in various branches of industry, and in scientific researches.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
C. L. Cao ◽  
C. G. Hu ◽  
L. Fang ◽  
S. X. Wang ◽  
Y. S. Tian ◽  
...  

The properties of the humidity sensors made of chemically treated and untreated multi-walled carbon nanotube (MWCNT) thin films are investigated systematically. It shows that both the chemically treated and untreated MWCNT thin films demonstrate humidity sensitive properties, but the former have stronger sensitivity than the latter. In the range of 11%–98% relative humidity (RH), the resistances of the chemically treated and untreated MWCNT humidity sensors increase 120% and 28%, respectively. Moreover, the treated humidity sensors showed higher sensitivity and better stability. In addition, the response and recover properties, and stabilization of the humidity sensors are measured, and the humidity sensitive mechanisms of the sensors are analyzed. The humidity sensitivity of carbon nanotube thin films indicates it promise as a kind of humidity sensitive material.


2007 ◽  
Vol 1054 ◽  
Author(s):  
Mike Taschuk ◽  
John Steele ◽  
Mike Brett

ABSTRACTCapacitive humidity sensors were fabricated using interdigitated electrodes coated with amorphous nanostructured TiO2 thin films grown by glancing angle deposition. The sensor exhibited a large change in capacitance, increasing exponentially from ∼ 1 nF to ∼ 1 μF for an increase in relative humidity from 2 % to 92 %. A simple model of the capacitive response and dielectric constant of the devices has been developed and compared to the experimental results. From this comparison, it is clear that the magnitude of the device response observed cannot be explained with bulk dielectric constants or literature values.


2020 ◽  
Vol 3 (1) ◽  
pp. 20-27
Author(s):  
Jiawei Bao ◽  
Niloofar Hashemi ◽  
Jingshuai Guo ◽  
Nicole N. Hashemi

Humidity sensors can be used to monitor body sweat. Here, we studied a humidity sensor that comprised of a graphene layer between two electrodes. The operating principle is that the humidity sensor will respond when vapor reaches the graphene layer from the top. Based on the humidity diffusion, the sensor measures the relative humidity (RH) with different response times. Graphene is a material with high diffusivity and small thickness that can increase the sensitivity of a sensor. Based on the micro electro mechanical systems (MEMS) method, we modeled the humidity sensor using COMSOL Multiphysics® transport of diluted species software. Additionally, we used the concentration values from the simulations to determine the relationship between capacitance and relative humidity. The sensitivity was found to be 3.379 × 10−11 pF/%RH for the 4-layer graphene, 1.210 × 10−14 pF/%RH for the 8-layer graphene, and 3.597 × 10−11 pF/%RH for the 16-layer graphene sensor. The sensitivity of 4-layer graphene with gold sensor is 3.872 × 10−13 pF/%RH which is smaller than 4-layer graphene sensor, and graphene with gold nanoparticles shows better response time than 4-layer graphene sensor.


2014 ◽  
Vol 21 (04) ◽  
pp. 1450048 ◽  
Author(s):  
DIL NAWAZ KHAN ◽  
MUHAMMAD HASSAN SAYYAD ◽  
MUHAMMAD TAHIR ◽  
FAZAL WAHAB ◽  
MUHAMMAD YASEEN ◽  
...  

In this paper, we have studied the effects of changing relative humidity on the electrical parameters and their multi frequency response of the surface type Ag /formyl- TIPPCu ( II )/ Ag humidity sensors. The silver electrodes of thickness 100 nm were primarily deposited on cleaned glass substrates by thermal evaporator. A gap of 40 μm was created between the electrodes of each device by using mask during the evaporation process. Thin films of formyl- TIPPCu ( II ) of 140 nm thickness were grown on silver electrodes by thermal sublimation technique. The values of capacitance and resistance of the sensors were found at different humidity levels at frequency of 1, 10 and 100 kHz of AC input signal. A remarkable increase in capacitance and decrease in resistance were observed during the rise of relative humidity from 45% to 95% RH. The hysteresis response of these humidity sensors was also studied at 1 kHz AC signal.


2021 ◽  
Author(s):  
F. Ostovari ◽  
E. Owji ◽  
H. Mokhtari Iran

Abstract In this research, optical humidity sensors based on etched-optical fibers coated with graphene Oxide (GO), silica gel (Sg) and a silica gel modified with GO (GSg) was studied. Their humidity sensing behavior was investigated by variation of relative differentiation of attenuation (RDA) in the presence of relative humidity (RH). As the results showed, etched fibers coated with Sg and GSg are highly capable of humidity sensing. However, a Sg- coated sample is not useful as humidity sensor related to sample coated by GSg because its RDA lacks a one-to-one correspondence with RH. As it was also found, the sensitivity of a GSg-coated sample is higher when the RH is below 40% and its repeatability is considerable.


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