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《功能材料》2015,(21)
采用静电纺丝法,分别选取不同的有机溶剂PVP,PMMA,制备了SnO2的有机物纳米纤维。在600℃温度下退火后,得到不同形貌的SnO2纳米材料(SnO2纳米纤维和SnO2纳米颗粒)。分别通过XRD,SEM,TEM,BET等表征方法对材料的微结构进行了表征,并分别制备了基于SnO2纳米纤维和SnO2纳米颗粒的气敏元件,测试了这些元件对(0.5~50)×10-6的甲醛气体的敏感性能。测试结果表明,在(0.5~50)×10-6甲醛浓度范围内,SnO2纳米颗粒气敏元件比SnO2纳米纤维气敏元件表现出更低的工作温度、更高的响应灵敏度和略长的响应及恢复时间。两种元件都对甲醛表现出良好的选择性。最后,分析了SnO2纳米材料对甲醛的吸附机理。 相似文献
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为了提高SnO2的气敏性能,以PVP为有机溶剂,采用静电纺丝法制备了多级结构的SnO2纳米纤维,利用XRD,SEM和TEM等技术对材料的结构、形貌进行了表征,并制备了SnO2旁热式气敏元件.采用静态气体测试系统对SnO2元件进行了气敏测试.在工作温度300℃时,对0.5~50 ppm甲醛进行了气敏测试.测试结果表明:SnO2气敏元件对甲醛气体具有优异的响应灵敏度,快速的响应及响应恢复特性、较好的选择性.采用静电纺丝制备的多级结构SnO2纳米纤维对甲醛表现出良好的气敏特性. 相似文献
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以ZnO、S如纳米颗粒及ZnO/SnO2复合纳米材料分别作为气敏基料制成旁热式气敏元件,运用扫描电镜观察产物的形貌,用静态配气法对浓度为100ppm的甲烷气体进行气敏性能的测试。结果表明,这几类元件的最佳工作温度及灵敏度差异较大,当工作温度为350℃时SnO2纳米颗粒的气敏性能最佳。此温度下,SnO2响应时间和恢复时间也比纯ZnO纳米颗粒分别缩短了2S和3S。 相似文献
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Post-treatment of the sensing film in tin oxide gas sensor arrays is widely used to improve the selectivity in gas recognition applications. This letter describes the characterization study of an integrated tin oxide gas sensor array chip in which the sensing films are modified using metal additives and ion implantations. Measurement results reveal that metal additives present a higher impact on the sensor sensitivity compared with ion implantations. The latter has no significant effect on the sensing properties. The drift is increased for the sensors with only ion implantation compared with the ones with metal additives. An array combining both post-treatment techniques is expected to improve the overall recognition performance. 相似文献
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K. K. Makhija Arabinda Ray R. M. Patel U. B. Trivedi H. N. Kapse 《Bulletin of Materials Science》2005,28(1):9-17
A sensor for ammonia gas and ethanol vapour has been fabricated using indium oxide thin film as sensing layer and indium tin
oxide thin film encapsulated in poly(methyl methacrylate) (PMMA) as a miniature heater. For the fabrication of miniature heater
indium tin oxide thin film was grown on special high temperature corning glass substrate by flash evaporation method. Gold
was deposited on the film using thermal evaporation technique under high vacuum. The film was then annealed at 700 K for an
hour. The thermocouple attached on sensing surface measures the appropriate operating temperature.
The thin film gas sensor for ammonia was operated at different concentrations in the temperature range 323–493 K. At 473 K
the sensitivity of the sensor was found to be saturate. The detrimental effect of humidity on ammonia sensing is removed by
intermittent periodic heating of the sensor at the two temperatures 323K and 448 K, respectively. The indium oxide ethanol
vapour sensor operated at fixed concentration of 400 ppm in the temperature range 293–393 K. Above 373 K, the sensor conductance
was found to be saturate. With various thicknesses from 150–300 nm of indium oxide sensor there was no variation in the sensitivity
measurements of ethanol vapour. The block diagram of circuits for detecting the ammonia gas and ethanol vapour has been included
in this paper. 相似文献
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Semiconducting tin oxide precursor powders were synthesized via three different chemical processing routes. The influence of powder processing conditions on the physical properties, e.g., particle size, surface area and phase composition of both uncalcined and calcined materials, was investigated. These powders were used to fabricate gas sensors using thick-film screen-printing technology. The effect of precursor powders, sintering conditions, sensor temperature and Pd catalyst on the carbon monoxide, methane, propane and ethanol gas sensing characteristics of the sensors were investigated. Sensors were also fabricated using tin oxide powders obtained from a commercial source and their gas sensing properties were also investigated. The data indicates that the powder processing methodology, sensor fabrication conditions and Pd catalyst can profoundly influence the physical characteristics as well as the gas sensing properties of the sensors. 相似文献
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Detection of Moisture and Methanol Gas Using a Single Electrospun Tin Oxide Nanofiber 总被引:1,自引:0,他引:1
This letter reports the fabrication of a gas sensor based on a single tin oxide nanofiber made from dimethyldineodecanoate tin using electrospinning and metallorganics decomposition techniques. The fabricated sensor has been used to detect moisture and methanol gas. It showed high sensitivity to both gases and the response times of the complete testing system are in the range of 108-150 s for moisture, and 10-38 s for methanol gas, respectively. 相似文献
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Helwig A. Muller G. Weidemann O. Hartl A. Garrido J.A. Eickhoff M. 《IEEE sensors journal》2007,7(9):1349-1353
Hydrogenated diamond (HD) samples exhibit a p-type surface conductivity (SC) which is caused by transfer doping to an adsorbed liquid electrolyte layer. We report on gas sensing experiments showing that such samples selectively respond to NO2 and NH3 gases at room temperature. Successive substitution of H-terminated surface sites by O-termination ones causes an increase in both the sensor baseline resistance and the gas-induced resistance changes. Thermal desorption of the surface electrolyte layer, on the other hand, causes the sensor baseline resistance to increase and the gas sensing effect to disappear. Readsorption of the surface electrolyte reestablishes both the sensor baseline resistance and the gas sensing effect. Our results indicate that the gas sensing effect is caused by local pH-changes due to acid/base reactions of the adsorbed gas molecules in the surface electrolyte layer. It is argued that this dissociative gas sensing mechanism represents a valuable complement with regard to the established surface combustion mechanism that is operative on heated metal oxide surfaces. 相似文献
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The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of
pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films
of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ethanol vapours at 300°C. Aluminium oxide grains dispersed around
ZnO grains would result into the barrier height among the grains. Upon exposure of ethanol vapours, the barrier height would
decrease greatly leading to drastic increase in conductance. It is reported that the surface misfits, calcination temperature
and operating temperature can affect the microstructure and gas sensing performance of the sensor. The efforts are, therefore,
made to create surface misfits by doping Al2O3 into zinc oxide and to study the sensing performance. The quick response and fast recovery are the main features of this
sensor. The effects of microstructure and additive concentration on the gas response, selectivity, response time and recovery
time of the sensor in the presence of ethanol vapours were studied and discussed. 相似文献
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Although tin oxide has been the most widely investigated metal oxide material for gas detection, it suffers from the large resistance and high operating temperature. This could be overcome by hybridization with nanostructured carbon. In this work, tin oxide nanoparticles with ultrasmall sizes of 1-3 nm have been uniformly coated onto bundles of single-walled carbon nanotubes by a surfactant assisted solid state synthesis approach for the first time. Gas sensor properties of the as-synthesized nanocomposite material toward NO2 (from 5 to 60 ppm) are measured at 150 degrees C. Compared to the pure carbon tubes gas sensors, the nanocomposite gas sensor responds to NO2 in low concentrations with good linearity, high sensitivity, and fast recovery, while working at a relatively low temperature. 相似文献
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Palladium‐Decorated Silicon Nanomesh Fabricated by Nanosphere Lithography for High Performance,Room Temperature Hydrogen Sensing
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Min Gao Minkyu Cho Hyeuk‐Jin Han Yeon Sik Jung Inkyu Park 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(10)
A hydrogen (H2) gas sensor based on a silicon (Si) nanomesh structure decorated with palladium (Pd) nanoparticles is fabricated via polystyrene nanosphere lithography and top‐down fabrication processes. The gas sensor shows dramatically improved H2 gas sensitivity compared with an Si thin film sensor without nanopatterns. Furthermore, a buffered oxide etchant treatment of the Si nanomesh structure results in an additional performance improvement. The final sensor device shows fast H2 response and high selectivity to H2 gas among other gases. The sensing performance is stable and shows repeatable responses in both dry and high humidity ambient environments. The sensor also shows high stability without noticeable performance degradation after one month. This approach allows the facile fabrication of high performance H2 sensors via a cost‐effective, complementary metal–oxide–semiconductor (CMOS) compatible, and scalable nanopatterning method. 相似文献