scholarly journals Growth of MWCNTs on Plasma Ion-Bombarded Thin Gold Films and Their Enhancements of Ammonia-Sensing Properties Using Inkjet Printing

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Udomdej Pakdee ◽  
Ananya Thaibunnak
Keyword(s):  
Gas Sensor ◽  
Inkjet Printing ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Polymer Mixture ◽  
Multiwalled Carbon ◽  
Transparent Plastic ◽  
Plastic Substrates ◽  
Ammonia Sensing ◽  
Sensitivity And Selectivity

Multiwalled carbon nanotubes (MWCNTs) have been synthesized on thin gold (Au) films using thermal chemical vapor deposition (CVD). The films were evolved to catalytic Au nanoparticles (Au NPs) by plasma argon (Ar) ion bombardment with a direct current (DC) power of 216 W. The characteristics of the MWCNTs grown on Au catalysts are strongly dependent on the growth temperature in thermal CVD process. The MWCNTs were then purified by oxidation (550°C) and acid treatments (3 : 1 H2SO4/HNO3). After purifying the MWCNTs, they were dispersed in deionized water (DI water) under continuous sonication. The MWCNT solution was then ultrasonically dissolved in a conducting polymer mixture of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to prepare for an electronic ink. The ink was deposited onto the flexible and transparent plastic substrates such as polyethylene terephthalate (PET) with fabricated silver interdigitated electrode using two methods such as drop-casting and inkjet printing to compare in the detection of ammonia (NH3) and other volatile organic compounds (VOCs) at room temperature. Based on the results, the gas response, sensitivity, and selectivity properties of MWCNT-PEDOT:PSS gas sensor for NH3 detection are significantly enhanced by using inkjet printing technique. The sensing mechanism of fabricated gas sensor exposed to NH3 has been also proposed based on the swelling behaviour of polymer due to the diffusion of NH3 molecules into the polymer matrix. For the MWCNTs, they were mentioned as the conductive pathways for the enhancement of gas-sensing signals.

Metal-oxide based ammonia gas sensors: A review

2020 ◽  
Vol 10 ◽  
Author(s):  
Priya Gupta ◽  
Savita Maurya ◽  
Narendra Kumar Pandey ◽  
Vernica Verma
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Review Paper ◽  
Gas Sensing ◽  
Gas Sensitivity ◽  
Ammonia Gas ◽  
Ammonia Sensing ◽  
Ammonia Gas Sensors

: This review paper encompasses a study of metal-oxide and their composite based gas sensors used for the detection of ammonia (NH3) gas. Metal-oxide has come into view as an encouraging choice in the gas sensor industry. This review paper focuses on the ammonia sensing principle of the metal oxides. It also includes various approaches adopted for increasing the gas sensitivity of metal-oxide sensors. Increasing the sensitivity of the ammonia gas sensor includes size effects and doping by metal or other metal oxides which will change the microstructure and morphology of the metal oxides. Different parameters that affect the performances like sensitivity, stability, and selectivity of gas sensors are discussed in this paper. Performances of the most operated metal oxides with strengths and limitations in ammonia gas sensing application are reviewed. The challenges for the development of high sensitive and selective ammonia gas sensor are also discussed.

Defect-Controlled Gas Sensing Property of Nanostructured ZnO Films

2015 ◽  
Vol 814 ◽  
pp. 54-59
Author(s):  
Yong Qin Chang ◽  
Chang Jing Shao ◽  
Nan Jiang ◽  
Yan Jun Ma ◽  
Shi Qi Wang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Oxygen Vacancies ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Zno Films ◽  
Sensor Applications ◽  
Cvd Method ◽  
Short Recovery Time ◽  
Gas Sensing Properties ◽  
Ethanol Sensing

Nanostructured ZnO films were fabricated by chemical vapor deposition (CVD) method with different Sn source concentrations for ethanol sensing application. It was found that the morphology of the ZnO films were obviously affected by Sn concentration, while no any Sn signals were detected in the films. The response of the nanostructured ZnO films increases with the increase of ethanol concentrations, and the S2 sample displays the highest sensitivity. Thephotoluminescence spectra show that more oxygen vacancies exist in the S2 sample than the other samples, which reveals that oxygen vacancies may play a great role to improve the gas sensing properties of the ZnO films.A possible sensing mechanism was proposed to explain these phenomena.This work provides a very simple and efficient method to prepare ZnO gas sensor, its high response and short recovery time are also a merit for the ZnO films used in gas sensor applications.

scholarly journals A Set of Platforms with Combinatorial and High-Throughput Technique for Gas Sensing, from Material to Device and to System

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 606 ◽  
Author(s):  
Zhenghao Mao ◽  
Jianchao Wang ◽  
Youjin Gong ◽  
Heng Yang ◽  
Shunping Zhang
Keyword(s):  
Gas Sensor ◽  
High Throughput ◽  
System Integration ◽  
Sensor Array ◽  
Gas Sensing ◽  
Parallel Synthesis ◽  
Testing Platform ◽  
Long Time ◽  
Sensitivity And Selectivity ◽  
Array Optimization

In a new E-nose development, the sensor array needs to be optimized to have enough sensitivity and selectivity for gas/odor classification in the application. The development process includes the preparation of gas sensitive materials, gas sensor fabrication, array optimization, sensor array package and E-nose system integration, which would take a long time to complete. A set of platforms including a gas sensing film parallel synthesis platform, high-throughput gas sensing unmanned testing platform and a handheld wireless E-nose system were presented in this paper to improve the efficiency of a new E-nose development. Inkjet printing was used to parallel synthesize sensor libraries (400 sensors can be prepared each time). For gas sensor selection and array optimization, a high-throughput unmanned testing platform was designed and fabricated for gas sensing measurements of more than 1000 materials synchronously. The structures of a handheld wireless E-nose system with low power were presented in detail. Using the proposed hardware platforms, a new E-nose development might only take one week.

scholarly journals A Gas Sensing Channel Composited with Pristine and Oxygen Plasma-Treated Graphene

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 625 ◽  
Author(s):  
Haiyang Wu ◽  
Xiangrui Bu ◽  
Minming Deng ◽  
Guangbing Chen ◽  
Guohe Zhang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Carrier Transport ◽  
Oxygen Plasma ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Oxygen Plasma Treatment ◽  
Pristine Graphene ◽  
Composite Channel ◽  
Transport Path ◽  
Grown Graphene

Oxygen plasma treatment has been reported as an effective way of improving the response of graphene gas sensors. In this work, a gas sensor based on a composite graphene channel with a layer of pristine graphene (G) at the bottom and an oxygen plasma-treated graphene (OP-G) as a covering layer was reported. The OP-G on top provided oxygen functional groups and serves as the gas molecule grippers, while the as-grown graphene beneath serves as a fast carrier transport path. Thus, the composite channel (OP-G/G) demonstrated significantly improved response in NH3 gas sensing tests compared with the pristine G channel. Moreover, the OP-G/G channel showed faster response and recovering process than the OP-G channel. Since this kind of composite channel is fabricated from chemical vapor deposited graphene and patterned with standard photolithography, the device dimension was much smaller than a gas sensor fabricated from reduced graphene oxide and it is favorable for the integration of a large number of sensing units.

scholarly journals Effect of MWCNTs Functionalization on Thermal, Electrical, and Ammonia-Sensing Properties of MWCNTs/PMMA and PHB/MWCNTs/PMMA Thin Films Nanocomposites

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2625
Author(s):  
Raina Aman Qazi ◽  
Rozina Khattak ◽  
Luqman Ali Shah ◽  
Rizwan Ullah ◽  
Muhammad Sufaid Khan ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Limit Of Detection ◽  
Multiwalled Carbon ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Ammonia Sensing ◽  
Chemically Modified ◽  
Pristine Mwcnts ◽  
Effective Dispersion ◽  
Amine Groups

Partially biodegradable polymer nanocomposites Poly(3-Hydroxybutyrate) (PHB)/MultiwalledCarbon Nanotubes (MWCNTs)/Poly(Methyl Methacrylate) (PMMA)and non-biodegradable nanocomposites (MWCNTs/PMMA) were synthesized, and their thermal, electrical, and ammonia-sensing properties were compared. MWCNTs were chemically modified to ensure effective dispersion in the polymeric matrix. Pristine MWCNTs (p-MWCNTs) were functionalized with –COOH (a-MWCNTs) and amine groups (f-MWCNTs). Then, PHB grafted multiwalled carbon nanotubes (g-MWNTs) were prepared by a ‘grafting to’ technique. The p-MWCNTs, a-MWCNTs, f-MWCNTs, and g-MWCNTs were incorporated into the PMMA matrix and PMMA/PHB blend system by solution mixing. The PHB/f-MWCNTs/PMMA blend system showed good thermal properties among all synthesized nanocomposites. Results from TGA and dTGA analysis for PHB/f-MWCNTs/PMMA showed delay in T5 (about 127 °C), T50 (up to 126 °C), and Tmax (up to 65 °C) as compared to neat PMMA. Higher values of frequency capacitance were observed in nanocomposites containing f-MWCNTs and g-MWCNTs as compared to nanocomposites containing p-MWCNTs and a-MWCNTs. This may be attributed to their excellent interaction and good dispersion in the polymeric blend. Analysis of ammonia gas-sensing data showed that PHB/g-MWCNTs/PMMA nanocomposites exhibited good sensitivity (≈100%) and excellent repeatability with a constant response. The calculated limit of detection (LOD) is 0.129 ppm for PHB/g-MWCNTs/PMMA, while that of all other nanocomposites is above 40 ppm.

scholarly journals Boron-doped few-layer graphene nanosheet gas sensor for enhanced ammonia sensing at room temperature

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 1007-1014 ◽  
Author(s):  
Shubhda Srivastava ◽  
Shubhendra K. Jain ◽  
Govind Gupta ◽  
T. D. Senguttuvan ◽  
Bipin Kumar Gupta
Keyword(s):  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Graphene Nanosheet ◽  
Ammonia Sensing ◽  
Layer Graphene ◽  
Sensing Applications ◽  
Boron Doped ◽  
Few Layer Graphene

A boron-doped few-layer LPCVD graphene sensor is successfully designed and demonstrated for enhanced NH3 gas sensing applications.

scholarly journals Ni-CNT Chemical Sensor for SF6 Decomposition Components Detection: A Combined Experimental and Theoretical Study

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3493 ◽  
Author(s):  
Yingang Gui ◽  
Xiaoxing Zhang ◽  
Peigeng Lv ◽  
Shan Wang ◽  
Chao Tang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Density Functional ◽  
Chemical Sensor ◽  
Theoretical Study ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Gas Sensitivity ◽  
Sensitivity And Selectivity ◽  
Sf6 Decomposition ◽  
Insulation Status

SF6 decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6 decomposition components, a Ni-modified carbon nanotube (Ni-CNT) gas sensor has been prepared to analyze its gas sensitivity and selectivity to SF6 decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT gas sensor presents an outstanding gas sensing property according to the significant change of conductivity during the gas molecule adsorption. The conductivity increases in the following order: H2S > SOF2 > SO2 > SO2F2. The limit of detection of the Ni-CNT gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6 decomposition components detection. In summary, the Ni-CNT gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.

Preparation and Gas Sensing Properties of Microrod ZnO Materials

2014 ◽  
Vol 492 ◽  
pp. 297-300
Author(s):  
Liu Fang Yang ◽  
Yu Lin Wang ◽  
Qin Hui Wang
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
High Sensitivity ◽  
Raw Material ◽  
Gas Sensing Properties ◽  
Sensitivity And Selectivity ◽  
Static Volumetric Method ◽  
Degree Of Crystallization ◽  
High Degree

Using zinc chloride solution and ammonia (25%) as raw material, with the presence of surfactant (CTAB), the microrod ZnO material was synthesized by the hydrothermal method. The phase composition and microstructure of the prepared ZnO material were characterized with XRD and SEM. The results show that the ZnO material possesses a high degree of crystallization, its diameter below 4 μm, and its length about 35 μm. The gas sensing property of gas sensor fabricated with the prepared ZnO material was evaluated via the static volumetric method. At the operating temperature of 200°C, the gas sensor has high sensitivity and selectivity to CH3COCH3.The gas sensing characterization was also discussed.

scholarly journals Preparation and Test of NH3 Gas Sensor Based on Single-Layer Graphene Film

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 965
Author(s):  
Ting Liang ◽  
Ruifang Liu ◽  
Cheng Lei ◽  
Kai Wang ◽  
Zhiqiang Li ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Gas Sensing ◽  
Graphene Film ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Si Substrates ◽  
Ammonia Sensing ◽  
Layer Graphene ◽  
Mems Technology

The ammonia sensing properties of single-layer graphene synthesized by chemical vapor deposition (CVD) were studied. The Au interdigitated electrode (IDE) was prepared by microelectromechanical systems (MEMS) technology, and then, the single-layer graphene was transferred to the IDE by wet transfer technology. Raman spectroscopy was used to monitor the quality of graphene films transferred to SiO2/Si substrates. Moreover, the theory of graphene’s adsorption of gases is explained. The results show that gas sensing characteristics such as response/recovery time and response are related to the target gas, gas concentration, test temperature, and so on. In the stability test, the difference between the maximum resistance and the minimum resistance of the device is 1 ohm without ammonia, the change is less than 1% of its initial resistance, and the repeatability is up to 98.58%. Therefore, the sensor prepared with high quality single-layer graphene has good repeatability and stability for ammonia detection.

A dimethyl methylphonate sensor based on HFIPPH modified SWCNTs

2022 ◽  
Author(s):  
Haiyang Wu ◽  
Yubin Yuan ◽  
Qiang Wu ◽  
Xiangrui Bu ◽  
Long Hu ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Self Assembly ◽  
High Performance ◽  
Gas Sensing ◽  
Detection System ◽  
High Sensitivity ◽  
Assembly Method ◽  
Sensitivity And Selectivity ◽  
Effect Transistor ◽  
Walled Carbon Nanotubes

Abstract In order to meet the requirements of ultra-fast real-time monitoring of sarin simulator with high sensitivity and selectivity, it is of great significance to develop high performance dimethyl methylphonate (DMMP) sensor. Herein, we proposed a DMMP sensor based on p-hexafluoroisopropanol phenyl (HFIPPH) modified self-assembled single-walled carbon nanotubes (SWCNTs) with field effect transistor (FET) structure. The self-assembly method provides a 4 nanometres thick and micron sized SWCNT channel, with high selectivity to DMMP. The proposed SWCNTs-HFIPPH based sensor exhibits remarkably higher response to DMMP than bare SWCNT based gas sensor within only few seconds. The gas sensing response of SWCNTs-HFIPPH based sensor for 1ppm DMMP is 18.2%, and the response time is about 10 seconds. What's more, the gas sensor we proposed here shows excellent selectivity and reproducibility, and the limitation of detection is as low as ppb level. The proposed method lays the foundation for miniaturization and integration of DMMP sensors, expecting to develop detection system for practical sarin sensing application.

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