scholarly journals Facile Chemical Bath Synthesis of SnS Nanosheets and Their Ethanol Sensing Properties

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2581 ◽  
Author(s):  
Wei Shan ◽  
Zhengqian Fu ◽  
Mingsheng Ma ◽  
Zhifu Liu ◽  
Zhenggang Xue ◽  
...  
Keyword(s):  
High Performance ◽  
Gas Sensing ◽  
Raw Materials ◽  
Orthorhombic Phase ◽  
Ethanol Vapor ◽  
Fast Response ◽  
Sensing Applications ◽  
Recovery Times ◽  
Response And Recovery ◽  
Ethanol Sensing

Tin(II) monosulfide (SnS) nanosheets were synthesized using SnCl4•5H2O and S powders as raw materials in the presence of H2O via a facile chemical bath method. Orthorhombic phase SnS nanosheets with a thickness of ~100 nm and lateral dimensions of 2~10 μm were obtained by controlling the synthesis parameters. The formation of a SnO2 intermediate is key to the valence reduction of Sn ions (from IV to II) and the formation of SnS. The gas sensors fabricated from SnS nanosheets exhibited an excellent response of 14.86 to 100 ppm ethanol vapor when operating at 160 °C, as well as fast response and recovery times of 23 s and 26 s, respectively. The sensors showed excellent selectivity for the detection of ethanol over acetone, methanol, and ammonia gases, which indicates the SnS nanosheets are promising for high-performance ethanol gas sensing applications.

Enhanced Gas Sensing of Tin Dioxide Based Sensor for Indoor Formaldehyde Application

2021 ◽  
Vol 16 (2) ◽  
pp. 337-342
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Shanyu Liu ◽  
Ying Wang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Fast Response ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Formaldehyde Sensing ◽  
Gas Response

Indoor formaldehyde detection is of great important at present. Using efficient solvothermal method, nanosheet-constructed and nanorod-constructed hierarchical tin dioxide (SnO2) microspheres were successfully synthesized in this work and used for the gas sensing material for indoor formaldehyde application. The as-prepared two kinds of SnO2 gas sensing materials were applied to fabricate the gas sensors and formaldehyde gas sensing experiments were carried out. The HCHO gas sensing tests indicate that the gas response of the nanosheet-constructed SnO2 microspheres is about 1.7 times higher than that of the nanorod-constructed SnO2 microspheres. In addition, both of the two SnO2 based gas sensors show almost fast response and recovery time to HCHO gas. For the nanosheet-constructed microspheres, the response value is estimated to be 32.0 at 350 °C to 60 ppm formaldehyde gas, while the response and recovery times are 7 and 5 s, respectively. The simple and efficient preparation method and improved gas sensing properties show that the as-synthesized hierarchical SnO2 microsphere that is constructed by a large amount of nanosheets exhibits significant potential application for the indoor formaldehyde sensing.

scholarly journals An Ethanol Vapor Sensor Based on a Microfiber with a Quantum-Dot Gel Coating

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 300 ◽  
Author(s):  
Siqi Hu ◽  
Guofeng Yan ◽  
Chunzhou Wu ◽  
Sailing He
Keyword(s):  
Quantum Dot ◽  
Low Cost ◽  
Temperature Response ◽  
High Sensitivity ◽  
Ethanol Vapor ◽  
Fast Response ◽  
Cost System ◽  
Sensing Applications ◽  
Vapor Sensor ◽  
Ethanol Sensing

An ethanol vapor sensor based on a microfiber with a quantum-dot (QD) gel coating is proposed and demonstrated. The QD gel was made from UV glue as the gel matrix and CdSe/ZnS QDs with a concentration of 1 mg/mL. The drawing and coating processes were conducted by using a simple and low-cost system developed for this study. Bending, ethanol sensing, temperature response, and time response tests were carried out, respectively. The experimental results showed that the fabricated sensor had a high sensitivity of −3.3%/ppm, a very low temperature cross-sensitivity of 0.17 ppm/°C, and a fast response time of 1.1 s. The easily fabricated robust structure and the excellent sensing performance render the sensor a promising platform for real ethanol sensing applications.

NO2 Gas Sensor Based on SnSe/SnSe2p-n Hetrojunction

2021 ◽  
Vol 21 (9) ◽  
pp. 4779-4785
Author(s):  
Sanju Rani ◽  
Manoj Kumar ◽  
Yogesh Singh ◽  
Monika Tomar ◽  
Anjali Sharma ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Fast Response ◽  
Desorption Kinetics ◽  
Low Concentration ◽  
Sensing Applications ◽  
Recovery Times ◽  
Nanostructured Sensor ◽  
Evaporation Technique

Air pollution is a big concern as it causes harm to human health as well as environment. NO2 can cause several respiratory diseases even in low concentration and therefore an efficient sensor for detecting NO2 at room temperature has become one of the priorities of the scientific community. Although two dimensional (2D) materials (MoS2 etc.) have shown potential for NO2 sensing at lower temperatures, but these have poor desorption kinetics. However, these limitations posed by slow desorption can be overcome, if a material in the form of a p-n junction can be suitably employed. In this work, ~150 nm thick SnSe2 thin film has been deposited by thermally evaporating in-house made SnSe2 powder. The film has been studied for its morphological, structural and gas sensing applications. The morphology of the film showed that the film consists of interconnected nanostructures. Detailed Raman studies further revealed that SnSe2 film had 31% SnSe. The SnSe-SnSe2 nanostructured sensor showed a response of ~112% towards 5 ppm NO2 at room temperature (30 °C). The response and recovery times were ~15 seconds and 10 seconds, respectively. Limit of detection for NO2 was in sub-parts per million (sub-ppm) range. The device demonstrated a better response towards NO2 compared to NH3, CH4, and H2. The mechanism of room temperature fast response, recovery and selective detection of NO2 independent of humidity conditions has been discussed based on physisorption, charge transfer, and formation of SnSe-SnSe2 (p-n) nano-junctions. Depositing a nanostructured film consisting of nano-junctions using an industrially viable thermal evaporation technique for sensing a very low concentration of NO2 is the novelty of this work.

scholarly journals Bridging Nanowires for Enhanced Gas Sensing Properties

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 743
Author(s):  
Mohammad R Alenezi ◽  
Abdullah M. Almeshal
Keyword(s):  
High Performance ◽  
Gas Sensing ◽  
Fast Response ◽  
Growth Environment ◽  
Enhanced Sensitivity ◽  
Gas Sensing Properties ◽  
Response And Recovery ◽  
Nanowire Sensor ◽  
On Chip ◽  
Site Selective

It is crucial to develop new bottom-up fabrication methods with control over the physical properties of the active materials to produce high-performance devices. This article reports well-controlled, without seed layer and site-selective hydrothermal method to produce ZnO bridging nanowires sensors. By controlling the growth environment, the performance of the sensor became more efficient. The presented on-chip bridging nanowire sensor enhanced sensitivity toward acetone gas (200 ppm) around 63 and fast response time (420 ms) and recovery time (900 ms). The enhancement in the speed of response and recovery is ascribed to the exceptional NW-NW junction barrier that governs the sensor’s conductivity, and the excellent contact between ZnO nanowires and Au electrodes.

scholarly journals A Room-Temperature CNT/Fe3O4 Based Passive Wireless Gas Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3542 ◽  
Author(s):  
Tao Guo ◽  
Tianhao Zhou ◽  
Qiulin Tan ◽  
Qianqian Guo ◽  
Fengxiang Lu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Fast Response ◽  
Sensing Material ◽  
Recovery Times ◽  
Response And Recovery ◽  
Good Repeatability

A carbon nanotube/Fe3O4 thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe3O4 as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe3O4 based sensor performs well on sensing ammonia (NH3) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH3 gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.

ACETONE SENSING PROPERTIES OF HIERARCHICAL ZnO URCHINLIKE STRUCTURES BY HYDROTHERMAL PROCESS

2012 ◽  
Vol 24 (02) ◽  
pp. 99-103 ◽  
Author(s):  
Zheng Lou ◽  
Yingliang Feng ◽  
Xiangwei Liu ◽  
Lili Wang ◽  
Tong Zhang
Keyword(s):  
Gas Sensing ◽  
Operating Temperature ◽  
Hydrothermal Process ◽  
Hierarchical Structures ◽  
Fast Response ◽  
Hydrothermal Route ◽  
Recovery Times ◽  
Response And Recovery ◽  
The Individual ◽  
Excellent Selectivity

The nanorods bundles (urchinlike) ZnO microspheres, consisting of closely packed nanorods with wideness of about 50 nm, have been successfully synthesized by a hydrothermal route at the temperature of 140°C. The individual hierarchical ZnO microsphere ranged from 3.5 to 4.5 μm in diameter. Most importantly, ZnO hierarchical microsphere sensor exhibits excellent selectivity and fast response to acetone. Response and recovery times were 1 s and 3 s when the sensor was exposed to 100 ppm acetone at an operating temperature of 320°C. Thus, hierarchical structures play a significant role in the field of gas sensing.

scholarly journals Preparation, Characterization, and Mechanistic Understanding of Pd-Decorated ZnO Nanowires for Ethanol Sensing

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Deng ◽  
Shengbo Sang ◽  
Pengwei Li ◽  
Gang Li ◽  
Fanqin Gao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Operating Temperature ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
New Perspective ◽  
Ethanol Sensing ◽  
Higher Sensitivity

ZnO nanowires (ZnO-NWs) and Pd-decorated ZnO nanowires (Pd-ZnO-NWs) were prepared by hydrothermal growth and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). When used for gas sensing, both types of nanowires showed a good selectivity to ethanol but a higher sensitivity and lower operating temperature were found with Pd-ZnO-NWs sensors comparing to those of ZnO-NWs sensor. When exposed to 200 ppm ethanol, our ZnO-NWs sensor showed a sensitivity of about 2.69 at 425°C whereas 1.3 at. % Pd-ZnO-NWs sensor provided a 57% more detection sensibility at 325°C. In addition, both response and recovery times of Pd-ZnO-NWs sensors were significantly reduced (9 s) comparing to the ZnO-NWs. Finally, Pd-ZnO-NWs sensor also showed a much lower detection limit of about 1 ppm. The sensing mechanism of Pd-ZnO-NWs sensors has also been clarified, thereby providing a new perspective for further improvement of the sensing performance of ethanol sensors.

Zinc Oxide/Reduced Graphene Oxide Nanocomposites for Rapid Detection of Toluene Gas at Room Temperature

2020 ◽  
Vol 18 (10) ◽  
pp. 745-749
Author(s):  
Chih-Chia Wang ◽  
Chiu-Hung Liu ◽  
Hsuan-Hua Hsieh ◽  
Chih-Wei Tang ◽  
Chen-Bin Wang
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
Fast Response ◽  
Reduced Graphene ◽  
New Strategy ◽  
Recovery Times ◽  
Response And Recovery

In this study, a nanostructured zinc oxide/reduced graphene oxide (ZnO/rGO) composite was deposited on a quartz crystal microbalance (QCM) as a toluene gas sensor at room temperature. A series of ZnO, rGO and ZnO/rGO sensing materials was fabricated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Raman spectroscopy. There was significant efficiency of the ZnO/rGO composite on the sensing performance for toluene. For specific gas fluxes, the nanostructured ZnO/rGO offered sufficient paths and region for vapor diffusion and adsorption. The sensing test results illustrated that the nanostructured ZnO/rGO composite showed significant enhancement in the frequency shifts (△f) for toluene comparing to pure ZnO and rGO. Also, the ZnO/rGO-coated QCM sensor displayed a fast response (both the response and recovery times < 30 s) and reproducibility for sensing toluene gas at room temperature. We believe that the novel insights on ambient temperature gas sensing on nanostructured ZnO/rGO composite could provide a new strategy for preparing a highly efficient sensing materials.

Screen-Printed Fe2O3/ZnO thick films for gas sensing applications

2005 ◽  
Vol 2 (1) ◽  
pp. 25-39 ◽  
Author(s):  
K. Arshak ◽  
I. Gaidan ◽  
L. Cavanagh
Keyword(s):  
Gas Sensing ◽  
Response Times ◽  
Thick Films ◽  
Ethanol Vapor ◽  
Vapor Concentration ◽  
Resistance Change ◽  
Glass Substrates ◽  
Sensing Applications ◽  
Recovery Times ◽  
Composition Ratios

This paper investigates iron-oxide and zinc-oxide thick-films for gas sensing applications. The films were printed onto glass substrates with silver electrodes. The effects of propanol, methanol and ethanol vapor on the devices at room temperature (in the concentration range 500–2000ppm) were investigated. The percentage relative resistance change, ΔR = ((Rgas − Rair)/Rair) ×100, was seen to increase linearly with increasing gas vapor concentration. The sensitivity of the films to the gas vapor was determined from the slope of the graphs. It was observed that various film compositions showed a higher sensitivity to propanol than to methanol and ethanol. Moreover, the sensitivity to propanol increased from 0.077 to 0.166 to 0.173%/ppm for the three samples with molecular weight composition ratios of: 90%/10%, 80/20% and 70%/30% of Fe2O3 to ZnO respectively. The response times of sensors 1, 2 and 3 (to 1000ppm step changes in propanol concentration) were 48.6 seconds, 86.4 seconds and 76.5 seconds, while the recovery times were 117 seconds, 186 seconds and 153 seconds respectively.

scholarly journals Optimization of a Low-Power Chemoresistive Gas Sensor: Predictive Thermal Modelling and Mechanical Failure Analysis

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 783 ◽  
Author(s):  
Andrea Gaiardo ◽  
David Novel ◽  
Elia Scattolo ◽  
Michele Crivellari ◽  
Antonino Picciotto ◽  
...  
Keyword(s):  
Low Power ◽  
Failure Analysis ◽  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Mechanical Failure ◽  
Sensing Applications ◽  
Theoretical Approaches ◽  
Sensing Material ◽  
Silicon Bulk

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

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