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In this work, surface-type humidity sensors with P3HT (organic) and P3HT–TiO2 (organic–inorganic hybrid) active layers have been fabricated. The surface morphology of the humidity active films has been studied by atomic force microscopy, whereas their crystalline structure has been studied by X-ray diffraction. We have aimed at improving the sensin...
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Indium-zinc oxide (IZO) nanofiber matrices are synthesized on SiO 2 -covered silicon substrates by the electrospinning method. The nanofibers’ dimensions, morphology, and crystalline structure are characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results of studying the electrical properties of nanof...
Citations
... Reference Zafar et al. (2016) used a thin film of TMBHPET to observe the capacitance with changing relative humidity from 30 to 99%RH. Azmer et al. (2018) studied the capacitance variance of P3HT and P3HT-TiO 2 with changing relative humidity from 30 to 95%RH. A composite thin film of methyl orange and TiO 2 was used by Tahir et al. (2014a). ...
Purpose
The purpose of this study is to fabricate a highly sensitive humidity sensor for observing the humidity effect on a robot’s body as an application of the Internet of Things. The sensor has been fabricated by depositing a thin sensing layer of nickel phthalocyanine (NiPc) between two silver electrodes.
Design/methodology/approach
The structure of the thin film was observed by X-ray diffraction, optical properties by UV Vis and surface morphology by scanning electron microscope. The capacitance and the resistance with respect to change in relative humidity from 0 to 100%RH have been measured by LCR meter at 1 kHz.
Findings
The sensor’s response time is 7.5 s and its recovery time is 3.7 s, with high sensitivity of 127,259 pF/%RH and 332.287 MΩ/%RH. The authors have also used a proposed sensor on a steel body and observed humidity values. The analysis of all measured values was performed through the classical and neutrosophic approaches. By comparing, the authors have observed that the neutrosophic approach is more efficient in analyzing the sensor data.
Originality/value
In this work, the authors will fabricate a capacitive and resistive-type humidity sensor using the thin film of NiPc. The structural, optical and morphological properties of NiPc thin film will be investigated with different characterization techniques. The electric properties, i.e. capacitance and resistance, will be measured at intervals with an LCR meter by changing relative humidity (%RH). Moreover, the measured data will be analyzed through different statistical approaches, as already used in [12].
... The presence of water vapor in the environment leads to high moisture and high humidity condition. Humidity sensor is an instrument used to detect the humidity of surrounding and to monitor the environmental moisture (Mishra et al. 2021;Owji et al. 2021;Wu et al. 2021;Zheng et al. 2021), which is specifically important for human thermal comfort and industrial process applications (Chen and Lu 2005;Azmer et al. 2018;Lim et al. 2019;Shelke and Late 2019;Awais et al. 2020;Sathisha et al. 2020;ur Rehman et al. 2020). For instance, humidity sensor is used in the industry for humidity control in chemical gas purification, dryers, ovens, film desiccation, textile production and food processing (Chen and Lu 2005;Akram et al. 2021;Al-Haidary et al. 2021;Anisimov et al. 2021;Narwade et al. 2021). ...
In this study, capacitive humidity sensors based on grown poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) nanotubes and anodic aluminum oxide (AAO) template is fabricated and characterized. The active layer of the device consists of infiltrated PFO-DBT solution on AAO template, thereby growing the PFO-DBT nanotubes. Infiltration was performed by three different deposition methods, namely spin coating, immersion of AAO template in polymeric solution and deposition by vortex mixer. Results showed that each method yielded a large-scale production of PFO-DBT nanotubes with different specifications. The open-end of the PFO-DBT nanotubes at the top surface of the template acts as porous, which provides a larger sensing area for device, thus enhancing the performance of the device. Furthermore, the infiltrated PFO-DBT in the porous has significantly increased the sensitivity of the device compared to that of the used empty AAO template. The impact of distinct morphology of the structure on the electrical properties such as device sensitivity, hysteresis and its respond and recovery time are also investigated and elaborated.
... With a simple comparison between capacitive with resistive humidity sensor, the former show good linearity and greater stability at higher humidity levels. The operation mode of capacitive sensors involves the change in the dielectric constant for the used thin film as humidity sensing occurs with varying humidity levels [12,13]. The aim of this work was to increase the sensitivity for humidity by using P3HT with different metallic nanoparticles as an active material in manufacturing Al/ P3HT / metallic nanoparticles/Al. ...
Capacitive–resistive humidity sensors based on polythiophene (P3HT) organic semiconductor as an active material hybrid with three types of metallic nanoparticles (NP) (Ag, Al, and Cu) were synthesized by pulsed laser ablation (PLA). The hybrid P3HT/metallic nanoparticles were deposited on indium-tin-oxide (ITO) substrate at room temperature. The surface morphology of theses samples was studied by using field emission scanning electron micrographs (FE-SEM), which indicated the formation of nanoparticles with grain size of about 50nm. The electrical characteristics of the sensors were examined as a function of the relative humidity levels. The sensors showed an increase in the capacitance with variation in the humidity level. While the resistivity While the resistivity decrease nonlinearity in the variation of humidity level from 10% to 100%.. The results show that the recovery and response times were higher for the Al/P3HT/Cu/Al sensor compared with those of the other nanoparticles.
... Therefore, many studies for polymeric humidity sensors have been conducted. However, most of them focused on the improvement in the sensing performance by using new polymer composites [16][17][18] or adding inorganic materials [19][20][21]. Thus, it is necessary to investigate the effect of the intrinsic property of polymers on their humidity sensing performance. ...
Nowadays, humidity sensors have caused the wide attention, owing to their use in various areas of daily life. In this study, a new organic-inorganic hybrid humidity sensor with high capacitance sensitivity and fast response was fabricated on substrates of glass and flexible polyethylene terephthalate (PET) by ion beam sputtering polydimethylsiloxane deposition. The sensors showed extremely high sensitivity (295.3 ± 0.8 pF/%RH), when the humidity changed from 11% to 97%, the capacitance at 1 kHz increased from 4.0 pF to 25.4 nF by more than 3.5 orders of magnitude. The sensors showed excellent performance, with high sensitivity, fast response of 4.9 s and long-term stability. After the humidity sensing mechanism of the sensors was investigated, it was found that the high sensitivity and the stability of A-SPSD films are originated from the formation of numerous hydrophilic functional groups on the stable C–Si–O network. Therefore, the present study describes an excellent technique for creating high-performance humidity sensors by sputtering polydimethylsiloxane deposition on the substrate, and it offers a practical path for creating humidity and gas sensors.
The development of high-performance humidity sensors to cater for a plethora of applications, ranging from agriculture to intelligent medical monitoring systems, calls for the selection of a reliable and ultrasensitive sensing material. A simplistic device architecture, robust quantification of ambient relative humidity (% RH), and compatibility with the contemporary integrated circuit technology make a bimodal (capacitive and resistive) surface-type sensor to be a prominent choice for device fabrication. Herein, we have proposed and demonstrated a facile realization of a 5,10,15,20-tetraphenylporphyrinatonickel (II)-zinc oxide (TPPNi-ZnO) nanocomposite-based bimodal surface-type % RH sensor. The TPPNi macromolecule and ZnO nanoparticles have been synthesized by an eco-benign microwave-assisted technique and a thermal-budget chemical precipitation method, respectively. It is speculated from the morpohological study that specific surface area improvement, via the provision of ZnO nanoparticles on micro-pyramidal structures of TPPNi, may reinforce the sensing properties of the fabricated humidity sensor. The relative humidity sensing capacitive and resistive characteristics of the sensor have been monitored in 40-85% relative humidity (% RH) bandwidth. The fabricated sensor under the biasing conditions of 1 V of applied bias (V rms) and 500 Hz AC test frequency exhibits a significantly higher sensitivity of 387.03 pF/% RH and 95.79 kΩ/% RH in bimodal operation. The average values of both the response and recovery times of the capacitive sensor have been estimated to be ∼30 s. It has also been debated why this high degree of sensitivity and considerable reduction in response/recovery time has been obtained. In addition, the intense and wide bandwidth spectral response of the TPPNi-ZnO nanocomposite indicates that it may also be utilized as a potential light-harvesting heterostructured nanohybrid in future studies.
This paper proposes a signal processed systematic 3 × 3 humidity sensor array with all range and highly linear humidity response based on different particles size composite inks and different interspaces of interdigital electrodes (IDEs). The fabricated sensors are patterned through a commercial inkjet printer and the composite of Methylene Blue and Graphene with three different particle sizes of bulk Graphene Flakes (BGF), Graphene Flakes (GF), and Graphene Quantum Dots (GQD), which are employed as an active layer using spin coating technique on three types of IDEs with different interspaces of 300, 200, and 100 µm. All range linear function (0–100% RH) is achieved by applying the linear combination method of nine sensors in the signal processing field, where weights for linear combination are required, which are estimated by the least square solution. The humidity sensing array shows a fast response time (Tres) of 0.2 s and recovery time (Trec) of 0.4 s. From the results, the proposed humidity sensor array opens a new gateway for a wide range of humidity sensing applications with a linear function.
