Carbon Monoxide Sensing Technologies for Next-Generation Cyber-Physical Systems

Nandy, Turja; Coutu, Ronald A.; Ababei, Cristinel

doi:10.3390/s18103443

Cited by 78 publications

(70 citation statements)

References 107 publications

(156 reference statements)

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“…The three main characterization parameters for the performance of any sensor are sensitivity, response time, and recovery time. Response time is the time for responding to a step concentration change from 0 to 90% of the saturated value and recovery time is the time taken for the signal of the sensor to return to 90% of the initial value [ 50 ]. From the results in Figure 8 a,b, it is observed that the eight sensor array coated with the sensing material of SnO 2 and 0.2% Pd, gives 11.6 mV, compared to 4.1 mV in three sensor array, which is because of the additive effect of the potential.…”

Section: Resultsmentioning

confidence: 99%

Palladium-Doped Tin Oxide Nanosensor for the Detection of the Air Pollutant Carbon Monoxide Gas

Jebakumar

Juliet

2020

Sensors

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The exhaust gases from various sources cause air pollution, which is a leading contributor to the global disease burden. Hence, it has become vital to monitor and control the increasing pollutants coming out of the various sources into the environment. This paper has designed and developed a sensor material to determine the amount of carbon monoxide (CO), which is one of the major primary air pollutants produced by human activity. Nanoparticle-based sensors have several benefits in sensitivity and specificity over sensors made from traditional materials. In this study, tin oxide (SnO2), which has greater sensitivity to the target gas, is selected as the sensing material which selectively senses only CO. Tin oxide nanoparticles have been synthesized from stannous chloride dihydrate chemical compound by chemical precipitation method. Palladium, at the concentration of 0.1%, 0.2%, and 0.3% by weight, was added to tin oxide and the results were compared. Synthesized samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) techniques. XRD revealed the tetragonal structure of the SnO2 nanoparticles and FESEM analysis showed the size of the nanoparticles to be about 7–20 nm. Further, the real-time sensor testing was performed and the results proved that the tin oxide sensor, doped with 0.2% palladium, senses the CO gas more efficiently with greater sensitivity.

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Section: Resultsmentioning

confidence: 99%

Palladium-Doped Tin Oxide Nanosensor for the Detection of the Air Pollutant Carbon Monoxide Gas

Jebakumar

Juliet

2020

Sensors

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“…Carbon nanotubes received enormous attention over the last three decades due to their unique electrical, mechanical, and optical properties [25][26][27][28][29][30][31][32][33][34]. CNTs are capable of altering LC matrix chemistry, viscosity, dispersion quality, etc.…”

Section: Review On Condutivity Behavior Of Lc-cnt Dispersionsmentioning

confidence: 99%

Nematic Liquid Crystal Composite Materials for DC and RF Switching

2019

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Liquid Crystals (LCs) are widely used in display devices, electro-optic modulators, and optical switches. A field-induced electrical conductivity modulation in pure liquid crystals is very low which makes it less preferable for direct current (DC) and radio-frequency (RF) switching applications. According to the literature, a conductivity enhancement is possible by nanoparticle doping. Considering this aspect, we reviewed published works focused on an electric field-induced conductivity modulation in carbon nanotube-doped liquid crystal composites (LC-CNT composites). A two to four order of magnitude switching in electrical conductivity is observed by several groups. Both in-plane and out-of-plane device configurations are used. In plane configurations are preferable for micro-device fabrication. In this review article, we discussed published works reporting the elastic and molecular interaction of a carbon nanotube (CNT) with LC molecules, temperature and CNT concentration effects on electrical conductivity, local heating, and phase transition behavior during switching. Reversibility and switching speed are the two most important performance parameters of a switching device. It was found that dual frequency nematic liquid crystals (DFNLC) show a faster switching with a good reversibility, but the switching ratio is only two order of magnitudes. A better way to ensure reversibility with a large switching magnitude is to use two pairs of in-plane electrodes in a cross configuration. For completeness and comparison purposes, we briefly reviewed other nanoparticle- (i.e., Au and Ag) doped LC composite’s conductivity behavior as well. Finally, based on the reported works reviewed in this article on field induced conductivity modulation, we proposed a novel idea of RF switching by LC composite materials. To support the idea, we simulated an LC composite-based RF device considering a simple analytical model. Our RF analysis suggests that a device made with an LC-CNT composite could show an acceptable performance. Several technological challenges needed to be addressed for a physical realization and are also discussed briefly.

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“…Another important issue is creation of residential and automotive environment so it is so necessary fast and sensitive detection. Difficulty in detecting very low levels and continuous CO formation in the air poses problems [5].…”

Section: Introductionmentioning

confidence: 99%

Metal Oxide Gas Sensors by Nanostructures

Sarf¹

2020

Gas Sensors

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Recently, metal oxide gas sensors by nanostructures have stirred interest and have found their way in many applications due to their high sensitivity, material design compliance and high safety properties. Gas performance tests of n-type ZnO, Al-doped ZnO and ZnO/MWCNT structures toward different type gases from our previous studies have been reported. It is indicated that nanoparticle formations on the film surfaces, grain sizes, gas types and operating temperatures have a severe effect on the chemisorption/physisorption process. Low concentration detection, determination of grain size limit values and reducing operating temperature to room temperature are already obstacles on long-life sensitivity and long-term stability characters. Doping is an effective way to increase gas sensitivity with atomic surface arrangement and active gas adsorption sites, which are generated by doping atoms. However, C-based material/MO nanostructures are preferred than doped MO films with their working even at room temperature. Up to now, a lot of methods to improve the gas sensitivity has been proposed. With the help of the development of surface modification methods such as different types of doping and MO-C composite, sensitivity, which is the most important parameter of sensor performance, can also be stable as well as increasing later on.

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Carbon Monoxide Sensing Technologies for Next-Generation Cyber-Physical Systems

Cited by 78 publications

References 107 publications

Palladium-Doped Tin Oxide Nanosensor for the Detection of the Air Pollutant Carbon Monoxide Gas

Palladium-Doped Tin Oxide Nanosensor for the Detection of the Air Pollutant Carbon Monoxide Gas

Nematic Liquid Crystal Composite Materials for DC and RF Switching

Metal Oxide Gas Sensors by Nanostructures

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