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Gas sensors

Priyanka Garg, Indrani Choudhuri, Biswarup Pathak
Density functional theory calculations are performed to investigate the gas sensing properties (NO, NO2, NH3 and N2O) of pure and doped (B@, N@, and B-N@) stanene. Dispersion corrected (DFT-D3) density functional calculations show that doping improves the interaction between stanene and gas molecules. The extent of interaction between the system and gas molecules is further studied through charge density difference (CDD), electrostatic potential (ESP) and Bader charge analysis. The electronic properties of pure stanene + gases are studied with and without the effect of spin-orbit coupling...
November 17, 2017: Physical Chemistry Chemical Physics: PCCP
Richard Gondosiswanto, David Brynn Hibbert, Yu Fang, Chuan Zhao
Ionic liquids have been regarded as promising electrolytes as substitutes for volatile aqueous or organic solvents for electrochemical gas sensors. However ionic liquids are viscous and the slow diffusion of gas molecules leads to poor sensitivity and sluggish response times. Herein, we describe a strategy using an array of microstrips of ionic liquid containing magnetic nanoparticles as nano-stirrers for enhanced mass transport and gas sensing. Magnetic CoFe2O4 nanoparticles are synthesized and dispersed in a hydrophobic ionic liquid [BMP][Ntf2]...
November 16, 2017: ACS Applied Materials & Interfaces
Jae-Hyoung Lee, Jin-Young Kim, Jae-Hun Kim, Ali Mirzaei, Hyoun Woo Kim, Sang Sub Kim
One-dimensional, hollow nanostructured materials are among the most promising materials for sensing applications owing to their high surface area that facilitates the adsorption of target gases. Accordingly, for gas sensing studies, hollow ZnO nanowires (NWs) with different surface areas were successfully synthesized herein by using polycarbonate membranes with different pore sizes as templates, and deposition of ZnO via the atomic layer deposition technique. The sensing properties of the synthesized hollow ZnO NWs were examined for CO and NO2, revealing their comparative sensing performances with ZnO nanomaterials-based sensors reported in literature...
2017: Nano Convergence
Yuechuan Lin, Wei Jin, Fan Yang, Yanzhen Tan, Hoi Lut Ho
We report performance optimization of hollow-core photonic bandgap fiber (HC-PBF) photothermal (PT) gas sensors. The PT phase modulation efficiency of a C2H2 filled HC-PBF (HC-1550-02) is found independent of the pump modulation frequency for up to ∼330  kHz, but starts to drop quickly to 10% of the maximum value at a couple of megahertz. With a 1.1 m long HC-PBF gas cell with angle-cleaved single-mode fiber/HC-PBF joints to reduce reflection and a modified 3×3 Sagnac interferometer with balanced detection for phase demodulation, a noise equivalent concentration of ∼67  ppbC2H2 is achieved with a 1 s time constant, and it goes down to ∼18  ppb with 145 s integration time...
November 15, 2017: Optics Letters
Ming Dong, Chongxing Zhang, Ming Ren, Ricardo Albarracín, Rixin Ye
Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately generates several types of decomposition products. These SF₆ decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment...
November 15, 2017: Sensors
Peijun Shi, Jifen Wang, Yadong Zhao, Yuai Duan, Lin Shi, Yue Hou, Jingdan Hou, Wenjun Li, Tianyu Han
Two solid emitters DMA and HBA were synthetized, showing aggregation-induced emission (AIE) phenomenon. Incorporation of electron donor-acceptor (D-A) pairs endows the solid emitters with both charge transfer (CT) state emission and distinct solvatochromic effect. The compounds undergo a rapid interaction with amines followed by the resulting weakened electron withdrawing ability to yield florescent products with either hypochromatic shift or decrease in the emission intensity. DFT calculations on HOMO and LUMO electronic cloud distribution and energy levels have demonstrated that the transition from CT state to locally excited (LE) state is mainly responsible for the spectral changes...
February 1, 2018: Talanta
Daniel Matatagui, Oleg Kolokoltsev, José Manuel Saniger, Isabel Gràcia, María Jesús Fernández, Jose Luis Fontecha, María Del Carmen Horrillo
Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%), good reproducibilities, and different responses for each detected solvent...
November 14, 2017: Sensors
Murugan Lalitha, Senthilkumar Lakshmipathi
The complete reduction of graphene oxide is difficult to achieve, and hence oxygen-containing functional groups do exist in graphene, along with structural defects. On the other hand, efficient gas sensor materials have been a subject of relentless interest. This instigates the need to explore the gas adsorption on STW and ISTW defective graphene sheets functionalised by -COOH, -OH and C-O-C groups, using density functional theory calculations. Both defects are experimentally feasible as evident through their formation energies...
November 14, 2017: Physical Chemistry Chemical Physics: PCCP
Jiu Pang, Qun Yang, Xiaosong Ma, Liming Wang, Chunjian Tan, Daxi Xiong, Huaiyu Ye, Xianping Chen
The sensing performances of pristine and X-doped phosphorene substrates (X = Al, Si, and S atoms) toward the adsorption of the toxic gases HCN and HNC were systematically investigated by first-principles simulations. The numerical results show that the pristine phosphorene is sensitive to HCN and HNC molecules with moderate adsorption energy, excellent charge transfer, high sensitivity and selectivity, implying its potential applications as excellent HCN and HNC sensors. In addition, the Al-doped phosphorene exhibits extremely high reactive activity toward HCN and HNC gases; thus, it has potential for use as a metal-free catalyst for activating or catalyzing HCN or HNC adsorbates...
November 14, 2017: Physical Chemistry Chemical Physics: PCCP
Yong Tian, Xiaomin Zhang, Hui-Yan Shen, Aifeng Liu, Zongshan Zhao, Ming-Li Chen, Xuwei Chen
High-time resolution monitoring nitrogen dioxide (NO2) is of great importance for studying the formation mechanism of aerosol and improving air quality. Based on the Griess-Saltzman (GS) reaction, a portable NO2 optical sensor was developed by employing a porous polypropylene membrane tube (PPMT) integrated gas permeation collector and detector. The PPMT was filled with GS reagents and covered with a coaxial jacket tube for gas collection. Its two ends were respectively fixed with a yellowish green light emitting diode and a photodiode for optic signal reception...
November 14, 2017: Analytical Chemistry
Fengjiang Zhang, Hao Dong, Xuanlang Zhang, Jin Guo, Yunqing Liu, Cheng Zhou, Xi Zhang, Jun Liu, Min Yan, Xing Chen
Propofol (2,6-diisopropylphenol) is widely used in total intravenous anesthesia. An unknown drug concentration in blood always leads to some side effects in patients with propofol injection. However, the drug concentration in the blood is hard to be continuously measured since invasive sampling causes a loss of blood at each measurement. Here, we introduced a virtual surface acoustic wave sensor array (VSAWSA) to non-invasively detect the propofol concentration in blood through exhaled gases. Calibration was conducted by a parallel test using gas chromatography and mass spectrometry (GC-MS) with solid-phase micro-extraction (SPME) for preconcentration...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Seohyun Mun, Yoonkyung Park, Yong-Eun Koo Lee, Myung Mo Sung
A highly sensitive Organic field-effect transistor (OFET)-based sensor for ammonia in the range of 0.01 to 25 ppm was developed. The sensor was fabricated by employing an array of single-crystal Poly(3-hexylthiophene) (P3HT) nanowires as the organic semiconductor (OSC) layer of an OFET with a top-contact geometry. The electrical characteristics (field-effect mobility, on/off current ratio) of the single-crystal P3HT nanowire OFET were about two orders of magnitude larger than those of the P3HT thin film OFET with the same geometry...
November 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Ya-Nan Zhang, Yong Zhao, Tianmin Zhou, Qilu Wu
Photonic crystal (PC) cavities, which possess the advantages of compactness, flexible design, and suitability for integration in a lab-on-a-chip system, are able to distinguish slight variations in refractive index with only a small amount of analyte. Combined with the newly proposed optofluidic technology, PC-cavity devices stimulate an emerging class of miniaturized and label-free biochemical sensors. In this review, an overview of optofluidic PC cavities based biochemical sensors is presented. First, the basic properties of the PC, as well as the sensing principle of the PC cavity, are discussed...
November 10, 2017: Lab on a Chip
Ming-Yen Chuang, Chang-Chiang Chen, Hsiao-Wen Zan, Hsin-Fei Meng, Chia-Jung Lu
In this work, a TFB (poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-s-butylphenyl)diphenylamine)]) sensor with a cylindrical nanopore structure exhibits a high sensitivity to ammonia in ppb-regime. The lifetime and sensitivity of the TFB sensor were studied and compared to those of P3HT (poly(3-hexylthiophene)), NPB (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), and TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine]) sensors with the same cylindrical nanopore structures...
November 17, 2017: ACS Sensors
Samereh Falahatkar, Seyed Mohsen Mousavi, Manochehr Farajzadeh
CO2 concentration (XCO2) shows the spatial and temporal variation in Iran. The major purpose of this investigation is the assessment of the spatial distribution of carbon dioxide concentration in the different seasons of 2013 based on the Thermal And Near Infrared Sensor for Carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) level 2 GOSAT data by implementing the ordinary kriging (OK) method. In this study, the Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) data from the MODerate resolution Imaging Spectroradiometer (MODIS), and metrological parameters (temperature and precipitation) were used for the analysis of the spatial distribution of CO2 over Iran in 2013...
November 9, 2017: Environmental Monitoring and Assessment
Taha Ayari, Chris Bishop, Matthew B Jordan, Suresh Sundaram, Xin Li, Saiful Alam, Youssef ElGmili, Gilles Patriarche, Paul L Voss, Jean Paul Salvestrini, Abdallah Ougazzaden
The transfer of GaN based gas sensors to foreign substrates provides a pathway to enhance sensor performance, lower the cost and extend the applications to wearable, mobile or disposable systems. The main keys to unlocking this pathway is to grow and fabricate the sensors on large h-BN surface and to transfer them to the flexible substrate without any degradation of the performances. In this work, we develop a new generation of AlGaN/GaN gas sensors with boosted performances on a low cost flexible substrate...
November 9, 2017: Scientific Reports
Lifang Gao, Xu Yang, Yang Shu, Xuwei Chen, Jianhua Wang
HYPOTHESIS: A novel slab optical waveguide sensor exploiting an ionic liquid (trihexyl(tetradecyl)phosphonium chloride)-based film can be used to detect gaseous ammonia. Bromothymol blue (BTB) incorporated into the ethyl cellulose-supported ionic liquid film can absorb the evanescent wave generated in the sensor and act as an indicator. The diffusion of gaseous ammonia across the sensing film is thus expected to change the absorbance of bromothymol blue, providing the basis for sensitive ammonia detection...
October 31, 2017: Journal of Colloid and Interface Science
Po-Jen Chien, Takuma Suzuki, Masato Tsujii, Ming Ye, Isao Minami, Kanako Toda, Hiromi Otsuka, Koji Toma, Takahiro Arakawa, Kouji Araki, Yasuhiko Iwasaki, Kayoko Shinada, Yoshihiro Ogawa, Kohji Mitsubayashi
This study describes two biosniffers to determine breath acetone and isopropanol (IPA) levels and applies them for breath measurement in healthy subjects and diabetic patients. Secondary alcohol dehydrogenase (S-ADH) can reduce acetone and oxidize nicotinamide adenine dinucleotide (NADH to NAD(+)) in a weak acid environment. NADH can be excited by 340 nm excitation lights and subsequently emit 490 nm fluorescence. Therefore, acetone can be measured by the decrease in NADH fluorescence intensity. S-ADH can also oxidize IPA and reduce NAD(+) to NADH when it is in an alkaline environment...
November 9, 2017: Analytical Chemistry
Marina Rumyantseva, Ekaterina Makeeva, Alexander Gaskov, Nikolay Shepel, Svetlana Peregudova, Andrey Khoroshutin, Sergey Tokarev, Olga Fedorova
This paper deals with the functionalization of nanocrystalline SnO₂ with Cu(II) complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO₂ hybrid material complexes of Cu(II) with phthalocyanine, porphyrinines, bipyridine and azadithiacrown etherwere used. The analysis of gas sensor properties showed the possibility of increasing the sensitivity and selectivity of hybrid materials in H₂S detection due to the electron transfer from SnO₂ to an adsorbed organic molecule, which changes during the interaction between H₂S and Cu(II) ions...
November 9, 2017: Nanomaterials
Simas Rackauskas, Nadia Barbero, Claudia Barolo, Guido Viscardi
This article provides an overview of the recent development of ZnO nanowires (NWs) for chemoresistive sensing. Working mechanisms of chemoresistive sensors are unified for gas, ultraviolet (UV) and bio sensor types: single nanowire and nanowire junction sensors are described, giving the overview for a simple sensor manufacture by multiple nanowire junctions. ZnO NW surface functionalization is discussed, and how this effects the sensing is explained. Further, novel approaches for sensing, using ZnO NW functionalization with other materials such as metal nanoparticles or heterojunctions, are explained, and limiting factors and possible improvements are discussed...
November 9, 2017: Nanomaterials
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