Preparation and properties of humidity sensor based on K-doped ZnO nanostructure

Gu, Yang; Ye, Zi; Sun, Ning; Kuang, Xuliang; Liu, Weijing; Song, Xiaojun; Zhang, Lei; Bai, Wei; Tang, Xiaodong

doi:10.1007/s10854-019-02230-y

Cited by 14 publications

(8 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…OH − , H + , Zn 2+ , Sn 4+ , and the oxygen on the surface chemically form a hydroxyl group, which is defined as chemical adsorption. The chemical expression that occurs on the surface of the material is [ 21 ]

{normalH}_{2} O + {normalO}_{normalO} + 2 {Zn}_{Zn} \Leftrightarrow 2 false(OH - Sn false) + V^{OO} + 2 {normale}^{-}

where

O_{normalO}

is lattice oxygen,

{Zn}_{Zn}

is the lattice of zinc, and

{normalV}^{OO}

is the oxygen vacancy at the oxygen position.…”

Section: Resultsmentioning

confidence: 99%

“…[ 15,16 ] Some groups have obtained remarkable sensing performance promotion through N, Co, and In doping in ZnO, respectively, as well as our previous works on the Ni‐ and K‐doped ZnO sensors. [ 17–21 ] Sn (Sn 4+ , 0.69 Å) has similar ionic radii with Zn (Zn 2+ , 0.74 Å). Hence, the Zn 2+ can be easily substituted by Sn 4+ during the growth of materials.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism

Wang

Zhang

et al. 2022

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

Humidity sensors have become a widespread and important integrated device for monitoring the environmental humidity in people's daily life to improve human comfort. They have already widely used for online real-time detection of automobile industry, medical field, construction, meteorology, and food processing. [1] Therefore, it is necessary to develop various humidity sensors with simple manufacturing, high sensitivity, and high-cost performance. Through domestic and overseas studies, it was found that metal oxides such as ZnO, SnO 2 , TiO 2 , In 2 O 3 , and WO 3 can meet the requirements of producing high-quality humidity sensors due to their small nanostructure size and large specific surface area. [2][3][4][5][6] Among the materials mentioned above, ZnO is a promising sensing material due to its wide energy bandgap (3.37 eV at room temperature) of n-type semiconductors, excellent chemical/physical stability, and unique electrical and optical properties. [7] Related studies have shown that 1D ZnO nanostructures have excellent sensing properties, such as high sensitivity, fast response/recovery, and have been used in humidity detection fields. [8][9][10][11][12][13][14] In order to meet the actual demand of production and life, the sensing characteristics of ZnO sensors need to be further improved. The chemical sensing ability of metal oxide materials can be enhanced by increasing the specific surface area and improving the surface state. Doping can effectively adjust the material characteristics such as specific surface area, surface state, and lattice structure strain, and it is considered as a valid method to modulate and enhance the performance of nanostructure humidity sensors. [15,16] Some groups have obtained remarkable sensing performance promotion through N, Co, and In doping in ZnO, respectively, as well as our previous works on the Ni-and K-doped ZnO sensors. [17][18][19][20][21] Sn (Sn 4þ , 0.69 Å) has similar ionic radii with Zn (Zn 2þ , 0.74 Å). Hence, the Zn 2þ can be easily substituted by Sn 4þ during the growth of materials. [22] With the doping process, the lattice structure of ZnO will be adjusted and more defects (e.g., oxygen vacancies) will be introduced, and the doped ions and defects can be directly or indirectly involved in the humidity-sensitive reaction, which enhances the humidity-sensitive properties.Among the methods for preparing materials, nonvacuum techniques or solution-based techniques such as hydrothermal, sol-gel, and spray pyrolysis have attracted a lot of attention from the scientific community due to their inexpensive nature. [23][24][25] In the above techniques, hydrothermal is the best choice for the preparation of nanowires because of its cost-effective and easy synthesis. [26] Precise positioning of nanostructures between electrodes is also necessary in the construction of sensors. Dielectrophoresis (DEP) has been widely used in many fields of research since its invention, such as biological cell separation, inorganic particle separation, material detection, manipulat...

show abstract

{normalH}_{2} O + {normalO}_{normalO} + 2 {Zn}_{Zn} \Leftrightarrow 2 false(OH - Sn false) + V^{OO} + 2 {normale}^{-}

where

O_{normalO}

is lattice oxygen,

{Zn}_{Zn}

is the lattice of zinc, and

{normalV}^{OO}

is the oxygen vacancy at the oxygen position.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism

Wang

Zhang

et al. 2022

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

show abstract

“…In particular, ZnO:K can be used in optoelectronic devices where a p–n junction is needed, since a stable p-type conductivity can be achieved [ 14 , 18 ]. In addition, control of the conductivity opens the door to other applications such as Graetzel solar cells (DSSCs) [ 12 ], devices for water decomposition by non-photocatalytic processes [ 15 ], humidity sensors [ 19 ], spintronic devices [ 10 , 17 , 20 ] and photocatalytic processes [ 11 ]. The possibility of obtaining composites formed by ZnO/K 2 SO 4 also increases the applicability of these structures as photocatalysts [ 9 ]…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of 2D Micro- and Nanostructures of ZnO:K

et al. 2022

View full text Add to dashboard Cite

ZnO nano- and microstructures doped with K were grown by the Vapor–Solid method. Wires and needles are the main morphology observed, although some structures in the form of ribbons and triangular plates were also obtained. Besides these, ball-shaped structures which grow around a central wire were also detected. Raman and cathodoluminescence investigations suggest that variations in morphology, crystalline quality and luminescence emissions are related to the different lattice positions that K occupies depending on its concentration in the structures. When the amount is low, K ions mainly incorporate as interstitials (Ki), whereas K occupies substitutional positions of Zn (KZn) when the amount of K is increased. Electron Backscattered Diffraction shows that ribbons and triangular plates are oriented in the (0001) direction, which indicates that the growth of this type of morphologies is related to distortions introduced by the Ki since this position favors the growth in the (0001) plane. In the case of the ball-shaped structures, the compositional analysis and Raman spectra show that they consist of K2SO4. Finally, the capability of the elongated structures to act as waveguides and optical resonators was investigated. Due to the size of the K ion, practically double that of the Zn, and the different positions it can adopt within the ZnO lattice (Ki or KZn), high distortions are introduced that compromise the resonators performance. Despite this, quality factor (Q) and fineness (F) show acceptable values (80 and 10 at 544 nm, respectively), although smaller than those reported for doping with smaller size alkali, such as Li.

show abstract

“…Nevertheless, regardless of noticeable advantages of these sensors, they are in uenced by trials such as small permeability (regarding water molecules), irreversible adsorption/absorption (towards water, that is resulted in dealing with signi cant memory effects, besides the inadequate hysteresis), and low selectivity (versus H 2 O, compared to other organic/inorganic foreign species, especially volatile organic compounds, small sensitive) 16,17 . Albeit, doping different nanostructures to the existing sensors have partially promoted the active surface area, and accessed acceptable permeability and selectivity 18,19 .…”

Section: Introductionmentioning

confidence: 99%

Fluorescent lamp tungsten filament thermionic emission gun as a novel humidity optical sensor

Sherafat

Torabi-Monfared

Doroodmand

et al. 2021

Preprint

View full text Add to dashboard Cite

Detecting humidity is a continuing concern within important area such as structural health, food processing, industrial as well agricultural products. In this study, a novel humidity optical sensor is introduced based on the thermionic emission of tungsten filament of a fluorescent lamp. Estimated blue compliant using a charged coupling device camera (CCD) in optical image of the tungsten filament is considered as appropriate detection system for relative humidity (RH) sensing. . The fabricated optical sensor has acceptable linear range (2.0- 98 % RH), improved detection limit (<5.0 % RH), acceptable saturated limit (> 99.0 % RH), improved percentage of relative standard deviation (4.18%, n=2), adequate hysteresis (<4.0 % RH) and a shorter rise time (<5.0 s), respectively. The mechanism behind this detection system was based on the interaction between H2O and tungsten filament during formation of WO3.x H2O (x = 1-2) based on the patented X-ray diffraction analysis.

show abstract

Preparation and properties of humidity sensor based on K-doped ZnO nanostructure

Cited by 14 publications

References 40 publications

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism

Optical Properties of 2D Micro- and Nanostructures of ZnO:K

Fluorescent lamp tungsten filament thermionic emission gun as a novel humidity optical sensor

Contact Info

Product

Resources

About

Preparation and properties of humidity sensor based on K-doped ZnO nanostructure

Cited by 14 publications

References 40 publications

High Sensitivity Humidity Sensors Based on Zn1−xSnxO Nanostructures and Plausible Sensing Mechanism

High Sensitivity Humidity Sensors Based on Zn1−xSnxO Nanostructures and Plausible Sensing Mechanism

Optical Properties of 2D Micro- and Nanostructures of ZnO:K

Fluorescent lamp tungsten filament thermionic emission gun as a novel humidity optical sensor

Contact Info

Product

Resources

About

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism

High Sensitivity Humidity Sensors Based on Zn_1−xSn_xO Nanostructures and Plausible Sensing Mechanism