Enhanced moisture sensing properties of a nanostructured ZnO coated capacitive sensor

Singh, Harinder; Kumar, Akshay; Bansod, Babankumar S.; Singh, Tejbir; Thakur, Anup; Singh, Tarandip; Sharma, Jeewan

doi:10.1039/c7ra10917b

Cited by 26 publications

(5 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure c shows the layout of the pore structure of the PVA humidity sensitive layer. The water vapor condensed easily due to the capillary action of the tiny pores; therefore, the porous structure can be considered as the active sites in the sensing process . It can be noted that these pores increase the specific surface area of the flexible sensor surface in contact with the outside gas, thus increasing the probability of the humidity sensitive layer surface capturing water molecules in the surrounding environment and improving the sensitivity of the flexible humidity sensor.…”

Section: Results and Discussionmentioning

confidence: 99%

Hysteresis Dynamic Modeling and Analysis of Flexible Nano Silver–Polyvinyl Alcohol Humidity Sensor Based on the Microscopic Process and Langmuir–Fick Theory

Xia

Wang

et al. 2022

ACS Omega

View full text Add to dashboard Cite

In recent years, advances in materials science and manufacturing technologies have facilitated the development of flexible sensors. However, there are still performance gaps between emerging flexible sensors and traditional silicon-based rigid sensors, especially lacking dynamic modeling and optimization analysis for addressing above challenges. This paper describes a hysteresis dynamic modeling method for flexible humidity sensors. Through inkjet printing and coating methods, the polyvinyl alcohol (PVA) sensitive layer and nano silver interdigital electrode are fabricated on flexible polyethylene naphthalate substrates. The performance characterization results show that the sensitivity and maximum hysteresis within the range of 12–98% relative humidity (RH) are −0.02167 MΩ/% RH and 2.7% RH, respectively. The sensor also has outstanding dynamic response ability and stability in a wide range of humidity variation. The hysteresis mechanism of flexible humidity sensors is theoretically analyzed from microscopic hysteresis processes, Langmuir monomolecular adsorption dynamic modeling, and Fick diffusion dynamic modeling. These hysteresis models provide a path for the hysteresis optimization of flexible PVA humidity sensors. Further exploration of the diffusion rate of water molecules and the proportion of PVA in ink represents promising hysteresis optimization directions of flexible humidity sensors based on PVA-sensitive material.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Hysteresis Dynamic Modeling and Analysis of Flexible Nano Silver–Polyvinyl Alcohol Humidity Sensor Based on the Microscopic Process and Langmuir–Fick Theory

Xia

Wang

et al. 2022

ACS Omega

View full text Add to dashboard Cite

show abstract

“…The humidity sensing mechanism responsible for the change in resistance depending on RH% is a process that includes chemical adsorption (chemisorption), physical adsorption (physisorption) and capillary condensation, and the Zn 2+ ions on the material surface and the morphology of the humidity-sensing metal oxide material are the critical parameters of this process [37,75,91,92]. According to figure 8, the resistances of BZO humidity sensors change quite rapidly at low relative humidity.…”

Section: Humidity Sensing Measurementsmentioning

confidence: 99%

“…At higher relative humidity levels, the number of water molecules adsorbed to the metal oxide surface will further increase. This causes the capillary pores to reach saturation, and then water vapor condenses in these pores [92]. As a result, at higher relative humidity levels, the resistance decreases significantly and saturates [93].…”

Section: Humidity Sensing Measurementsmentioning

confidence: 99%

Improved humidity sensing performances of boron doped ZnO nanostructured thin films depending on boron concentration

Algün,

Alshater,

Akçay

2024

Phys. Scr.

View full text Add to dashboard Cite

This study details the production and analysis of undoped zinc oxide (uZnO) and boron (B) doped zinc oxide nanostructured thin films, with a specific focus on assessing the influence of varying B doping concentrations on humidity sensing performance. The synthesis of undoped ZnO and B doped ZnO nanoparticles was carried out using sol-gel method. B doping concentrations within the ZnO lattice were adjusted to 1, 3, 4, 5, and 10 mol%. Subsequently, nanostructured thin films were obtained through the spin coating technique on glass substrates. X-ray diffraction analysis revealed a hexagonal wurtzite structure for all nanostructured thin films. Notably, a change in preferential orientation from the (002) plane to the (100) plane occurred when B doping concentration exceeded 5 mol%. Scanning electron microscopy showcased nano-sized grains and capillary nanopores on the surface of each thin film. Energy dispersive X-ray spectra confirmed the presence of zinc, oxygen, and boron elements in the nanostructured thin films. Humidity sensing performance was assessed through electrical resistance measurements in the range of 45–90% relative humidity at room temperature. All fabricated sensors exhibited sensitivity to humidity. Remarkably, the sensor with a 5 mol% B doping concentration demonstrated the highest humidity sensitivity (438.44 times) and the fastest response (2.0 s) and recovery times (14.2 s). The study concluded that the optimal B doping concentration for designing a highly efficient humidity sensor was determined to be 5 mol%. Overall, the study underscores the potential of B doped ZnO nanostructures for humidity sensor applications, given their exceptional sensor performance.

show abstract

“…The quantum confinement that occurs in quantum dots also makes their bandgap tunable depending on their size. Based on its property, its sensing performance can be altered by altering its size [55][56][57]. Moreover, the reactivity of the QDs is considerably high due to the many defects or oxygen vacancies present on their surface, increasing active sites for oxygen adsorption.…”

Section: Morphological Designmentioning

confidence: 99%

Advanced Strategies to Improve Performances of Molybdenum-Based Gas Sensors

et al. 2021

View full text Add to dashboard Cite

Molybdenum-based materials have been intensively investigated for high-performance gas sensor applications. Particularly, molybdenum oxides and dichalcogenides nanostructures have been widely examined due to their tunable structural and physicochemical properties that meet sensor requirements. These materials have good durability, are naturally abundant, low cost, and have facile preparation, allowing scalable fabrication to fulfill the growing demand of susceptible sensor devices. Significant advances have been made in recent decades to design and fabricate various molybdenum oxides- and dichalcogenides-based sensing materials, though it is still challenging to achieve high performances. Therefore, many experimental and theoretical investigations have been devoted to exploring suitable approaches which can significantly enhance their gas sensing properties. This review comprehensively examines recent advanced strategies to improve the nanostructured molybdenum-based material performance for detecting harmful pollutants, dangerous gases, or even exhaled breath monitoring. The summary and future challenges to advance their gas sensing performances will also be presented.

show abstract

Enhanced moisture sensing properties of a nanostructured ZnO coated capacitive sensor

Abstract: This work reports the enhancement in sensitivity of a simple and low-cost capacitive moisture sensor using a thin film of zinc oxide (ZnO) nanoparticles on electrodes.

Cited by 26 publications

References 57 publications

Hysteresis Dynamic Modeling and Analysis of Flexible Nano Silver–Polyvinyl Alcohol Humidity Sensor Based on the Microscopic Process and Langmuir–Fick Theory

Hysteresis Dynamic Modeling and Analysis of Flexible Nano Silver–Polyvinyl Alcohol Humidity Sensor Based on the Microscopic Process and Langmuir–Fick Theory

Improved humidity sensing performances of boron doped ZnO nanostructured thin films depending on boron concentration

Advanced Strategies to Improve Performances of Molybdenum-Based Gas Sensors

Contact Info

Product

Resources

About