scholarly journals Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

Nano Research ◽  
2021 ◽  
Author(s):  
Luis Antonio Panes-Ruiz ◽  
Leif Riemenschneider ◽  
Mohamad Moner Al Chawa ◽  
Markus Löffler ◽  
Bernd Rellinghaus ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Room Temperature ◽  
Sensor Array ◽  
High Selectivity ◽  
Electrochemical Sensors ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Electrical Characteristics ◽  
Sensor Fabrication ◽  
Walled Carbon Nanotubes

AbstractWe demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow, using a self-validating 64-channel sensor array based on semiconducting single-walled carbon nanotubes (sc-SWCNTs). The reproducible sensor fabrication process is based on a multiplexed and controlled dielectrophoretic deposition of sc-SWCNTs. The sensing area is functionalized with gold nanoparticles to address the detection at room temperature by exploiting the affinity between gold and sulfur atoms of the gas. Sensing devices functionalized with an optimized distribution of nanoparticles show a sensitivity of 0.122%/part per billion (ppb) and a calculated limit of detection (LOD) of 3 ppb. Beyond the self-validation, our sensors show increased stability and higher response levels compared to some commercially available electrochemical sensors. The cross-sensitivity to breath gases NH3 and NO is addressed demonstrating the high selectivity to H2S. Finally, mathematical models of sensors’ electrical characteristics and sensing responses are developed to enhance the differentiation capabilities of the platform to be used in breath analysis applications.

scholarly journals Ολοκληρωμένη συστοιχία αισθητήρων βασισμένη σε πολυμερή για την αναγνώριση πτητικών αερίων

2012 ◽  
Author(s):  
Πέτρος Οικονόμου
Keyword(s):  
Binary Mixtures ◽  
Sensor Array ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Principal Component ◽  
Polymeric Materials ◽  
Integrated Sensor ◽  
Electromagnetic Model ◽  
The Individual ◽  
Electronic Elements

In this research the sensor type of planar InterDigitated Capacitors (IDCs), also known as chemcapacitors, is demonstrated and its application in the detection of Volatile Organic Compounds (VOCs) and humidity is explored. The IDC layout configuration is studied by using a dedicated electromagnetic model and the behavior of different planar IDE structures/geometries coated with different polymeric materials of different dielectric permittivity values (εp) is determined. This study leads to the optimum design geometry of the planar IDCs that will be used for the detection of analytes. In order to identify the more suitable sensing materials for the targeted application, a methodology based on swelling measurements of the polymeric material upon exposure to analytes of interest was developed and applied in the prediction of the response of a chemcapacitor upon exposure to different VOCs. The integrated sensor array is characterized by the responses of each sensor to exposure to several pure analytes, binary mixtures of analytes and complex environments. Several parameters were examined such as sensitivity, selectivity, limit of detection, aging. Also the total response of the sensor array is analyzed by conjunction of the individual responses of each sensor and the use of suitable Principal Component Analysis, PCA, models that have been developed. Fabrication of a hybrid low-power gas sensing module is presented. This module is realized with integration on the same device of the sensor array with the appropriate electronic elements. The latter provide the power, control and read-out electronics of the output signal. The proposed hybrid micro-device is characterized in terms of the response of each sensor of the sensor array upon exposure to different pure analytes and their binary mixtures. Evaluation of the results obtained by the characterization of the hybrid gas sensing module demonstrate the ability of use such a device in analytical methods under conditions of constant or alterable concentration of VOCs/humidity or their mixtures in applications either at constant temperature or at temperature changing over time simulating that way real time applications.

Preliminary Study of WO3 Nanostructures Produced via Facile Hydrothermal Synthesis Process for CO2 Sensing

2013 ◽  
Vol 431 ◽  
pp. 37-41 ◽  
Author(s):  
Amirul Abd Rashid ◽  
Nor Hayati Saad ◽  
Chia Sheng Daniel Bien ◽  
Wai Yee Lee ◽  
M.A.S.M. Haniff
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Hydrothermal Reaction ◽  
Hydrothermal Process ◽  
Single Step ◽  
Synthesis Process ◽  
Sensor Element ◽  
Response Measurement ◽  
Sensor Fabrication ◽  
Preliminary Study

Tungsten trioxide (WO3) nanostructure with aspect ratio of 20 (length/diameter) have been successfully synthesized by single step hydrothermal reaction at moderate temperature of 180 °C. The crystal structure and morphology evolution are characterized by SEM and Raman while the carbon dioxide (CO2) sensing capability was tested by simple sensor fabrication .It was observed that the nanorods were initially coalesce in bundles before breaking up loosely towards the end of the hydrothermal process. A response measurement reveals that the sensor was able to detect CO2 at room temperature with the sensitivity around 13ohm/100 ppm. The detection performance of such nanostructure provides a positive indication that it can be a competitive sensor element candidate not only for CO2 applications in particular but can be expanded to other gas sensing application such as O2, C2H4 and NO2.

scholarly journals A Room Temperature Gas Sensor Based on Sulfonated SWCNTs for the Detection of NO and NO2

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1116 ◽  
Author(s):  
Eusebiu Ionete ◽  
Stefan Spiridon ◽  
Bogdan Monea ◽  
Elena Stratulat
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Electrical Response ◽  
Long Term Stability ◽  
Sensing Applications ◽  
Specific Configuration ◽  
P Type ◽  
Walled Carbon Nanotubes ◽  
Type Response

The electrical response of sulfonated single-walled carbon nanotubes (SWCNTs) to NO and NO2, for gas sensing applications, at room temperature, is reported in this work. A specific configuration based on SWCNT deposition between double pair configuration gold electrodes, supported on a substrate, was considered for the sensing device; employed characterization technique where FTIR and SEM. The experimental results showed a p-type response of the sulfonated SWCNTs, with decrease in resistance, under exposure to NO gas (40–200 ppb) and NO2 (40–200 ppb). Also, the sensor responses to successive exposures at NO2 800 ppb together with investigation of long term stability, at 485 ppb for NO, are reported. The reaction mechanism in case of NO and NO2 detection with sulfonated SWCNTs is presented.

Comparison of Hydrogen Sulfide Sensing Properties between Multiple-Walled Carbon Nanotubes (MWNTs) and MWNTs-HAuCl4 Materials

2014 ◽  
Vol 936 ◽  
pp. 310-314
Author(s):  
Si Xuan He ◽  
Guang Zhong Xie ◽  
Ya Dong Jiang ◽  
Guang Di Zhang ◽  
Yong Zhou
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Hydrogen Sulfide ◽  
Response Time ◽  
Room Temperature ◽  
The Other ◽  
High Toxicity ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

The rapid and precise detection of hydrogen sulfide (H2S) has great significance due to its high toxicity. In this work, the response properties of multiple-walled carbon nanotubes (MWNTs) and MWNTs-HAuCl4 to H2S at room temperature were compared. Scanning electron microscopy (SEM) technique was used to characterize MWNTs and MWNTs-HAuCl4 films. It was found that sensors with MWNTs-HAuCl4 exhibited much higher response value. On the other hand, sensors with MWNTs were observed to have faster response time and better recovery properties.

scholarly journals Facile Fabrication of Hybrid Carbon Nanotube Sensors by Laser Direct Transfer

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2604
Author(s):  
Anca F. Bonciu ◽  
Mihaela Filipescu ◽  
Stefan I. Voicu ◽  
Thomas Lippert ◽  
Alexandra Palla-Papavlu
Keyword(s):  
Room Temperature ◽  
Limit Of Detection ◽  
Theoretical Limit ◽  
Accurate Identification ◽  
Forward Transfer ◽  
Facile Fabrication ◽  
Multiple Cycles ◽  
Tin Oxide Nanoparticles ◽  
Walled Carbon Nanotubes ◽  
Hybrid Carbon

Ammonia is one of the most frequently produced chemicals in the world, and thus, reliable measurements of different NH3 concentrations are critical for a variety of industries, among which are the agricultural and healthcare sectors. The currently available technologies for the detection of NH3 provide accurate identification; however, they are limited by size, portability, and fabrication cost. Therefore, in this work, we report the laser-induced forward transfer (LIFT) of single-walled carbon nanotubes (SWCNTs) decorated with tin oxide nanoparticles (SnO2 NPs), which act as sensitive materials in chemiresistive NH3 sensors. We demonstrate that the LIFT-fabricated sensors can detect NH3 at room temperature and have a response time of 13 s (for 25 ppm NH3). In addition, the laser-fabricated sensors are fully reversible when exposed to multiple cycles of NH3 and have an excellent theoretical limit of detection of 24 ppt.

scholarly journals Berlin Green Framework-Based Gas Sensor for Room-Temperature and High-Selectivity Detection of Ammonia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tingqiang Yang ◽  
Lingfeng Gao ◽  
Wenxuan Wang ◽  
Jianlong Kang ◽  
Guanghui Zhao ◽  
...  
Keyword(s):  
High Resistance ◽  
Active Sites ◽  
Density Functional ◽  
Room Temperature ◽  
High Selectivity ◽  
Gas Sensing ◽  
Response Recovery ◽  
Sensing Material ◽  
Agriculture Industry ◽  
Ammonia Detection

AbstractAmmonia detection possesses great potential in atmosphere environmental protection, agriculture, industry, and rapid medical diagnosis. However, it still remains a great challenge to balance the sensitivity, selectivity, working temperature, and response/recovery speed. In this work, Berlin green (BG) framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation. Vacancy in BG framework offers abundant active sites for ammonia absorption, and the absorbed ammonia transfers sufficient electron to BG, arousing remarkable enhancement of resistance. Pristine BG framework shows remarkable response to ammonia at 50–110 °C with the highest response at 80 °C, which is jointly influenced by ammonia's absorption onto BG surface and insertion into BG lattice. The sensing performance of BG can hardly be achieved at room temperature due to its high resistance. Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework, and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.

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.

Ethanol Gas Sensor Fabrication Based on ZnO Flower Like Nanorods

2020 ◽  
Vol 38 (3B) ◽  
pp. 85-97
Author(s):  
Abdulqader D. Faisal ◽  
Mofeed A. Jaleel ◽  
Fahad Z. Kamal
Keyword(s):  
Gas Sensor ◽  
Seed Layer ◽  
Room Temperature ◽  
Gas Sensing ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Sensor Fabrication ◽  
Synthesized Materials

Zinc oxide flower-like nanorods (ZnO NRs) was successfully synthesized via the hydrothermal method. The growth process was conducted with seed layer concentrations of 20mM. The as-synthesized nanostructures were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), and ultraviolet-visible (UV-VIS) spectrophotometer. The analysis results revealed a pure Wurtzite ZnO hexagonal nanostructures with preferred orientation (002) along the c-direction. The calculated band gap of average crystallite size is 3.2eV and 25 nm respectively. New designed, constructed and successfully calibrated for ethanol gas sensing was found. The ethanol gas sensor was fabricated at room temperature based on the ZnO NRs film. The synthesized materials proved to be a good candidate for the ethanol gas sensor. The optimum results of the gas sensor measurements of the synthesized gas sensor are as follows, the sensitivity, response time, and recovery time at 25 °C are 60%, 80 Seconds and 80 seconds respectively, and at 200 °C are 70%, 60 seconds and 50 seconds respectively.

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