甲苯传感器的制作及特性

采用溶胶-凝胶法制备了NASICON(钠超离子导体)固体电解质材料.利用XRD分析了所制备材料的结构,材料的平均粒径约为22nm.以NASICON为离子导电层,Sm_2O_3为敏感电极制作了具有良好敏感特性的C_7H_8气体传感器.在430℃工作温度下,器件对(5-50)×10~(-6)C_7H_8的灵敏度为-75mV/decade.并且对C_7H_8具有较高的选择性和良好的响应恢复特性,器件对5 × 10~(-6)和50×10~(-6)C_7H_8的响应时间分别为45和35秒,恢复时间分别为8和60秒.对器件的敏感机理做以简要的分析.     

LaFeO_3纳米纤维的制备及其气敏特性研究

采用静电纺丝方法制备了LaFeO3纳米纤维,利用电子扫描显微镜(SEM)、X-射线衍射(XRD)对其进行表征。所合成的LaFeO3纳米纤维材料作为敏感材料制作烧结型旁热式气敏元件,测试其气敏特性。结果表明,基于LaFeO3纳米纤维的气体传感器对于乙醇气体的最佳工作温度为200℃,对于浓度为500×10-6的乙醇气体,灵敏度为46,LaFeO3纳米纤维材料对乙醇具有快速的响应恢复速度。     

多孔纳米棒氧化锌的制备及其气敏特性

采用水热法制备表面多孔的纳米棒状氧化锌。利用X射线衍射(XRD)、扫描电子显微镜(SEM)对样品的结构和形貌进行表征。以表面多孔的棒状氧化锌作为敏感材料制成旁热式结构的气体传感器,并对样品在不同温度下对乙醇气体的灵敏度进行了测试。结果表明:在280℃下,样品对100×10-6乙醇气体的灵敏度约为27.9,响应恢复时间分别约为3s和10s,此结果约是表面无孔的纳米棒状氧化锌在相同条件下对乙醇气体灵敏度的4.8倍,并且是相同条件下干扰气体中灵敏度最大的丙酮气体的3.1倍,表明该器件具有良好的选择性。     

氧化锡纳米线的制备及其乙醇气体敏感性能

采用热蒸发法成功制备氧化锡纳米线。用X射线衍射、扫描电子显微镜和透射电子显微镜对所制备纳米线的晶格结构和表面形貌进行表征。所制材料为金红石氧化锡单晶结构,纳米线直径为50~200nm,长度为5~15μm,符合气-液-固生长机制。以氧化锡为气敏材料,制备了旁热式结构气敏元件,测试该元件对浓度范围为25×10^-6 ~500×10^-6 的乙醇气体环境的敏感性能。结果表明,该元件的最佳工作温度约为260℃;在25×10^-6 和500×10^-6 的乙醇气体中,灵敏度分别为7.54和111.01,响应时间为2~20s,恢复时间为5~33s;在测试范围内灵敏度与气体浓度具有良好的线性关系;7天内重复测量误差在5%以内,稳定性较好。     

花状SnO2的制备及其气敏特性的研究

以乙二醇(C2H6O2)为有机溶剂,采用溶剂热法制备了花状SnO2纳米材料,并将制备的SnO2制成旁热式气敏元件.通过XRD,SEM等测试手段对SnO2纳米材料进行了表征,并初步分析了气敏元件对丙酮的敏感机理.制备的SnO2材料是由粒径约为10 nm的颗粒有规则的堆叠而成的直径约为3～4μm的花瓣清晰的多孔分级花状结构.研究发现,气敏元件对丙酮气体有很好的响应灵敏度.在最佳工作温度(350℃)时,检测的丙酮体积分数最低为1×10-6.对100 ppm丙酮的响应及恢复时间分别为40和50 s.且气敏元件对丙酮气体的响应灵敏度远高于对苯、甲苯、甲醇、甲醛、氨等气体的响应灵敏度.     

Au掺杂花状In_2O_3微结构的制备及其气敏特性研究

采用水热法制备了不同浓度(0%,1%,3%和5%(摩尔分数))Au掺杂的花状In_2O_3微结构。利用X射线衍射仪(XRD)、X射线能谱分析仪(EDS)和扫描电子显微镜(SEM)对合成的In_2O_3的晶相、成分和微观形貌进行表征与分析。分析结果表明,制备的花状微结构的平均粒径约4μm,花状纳米片的厚度约为25nm。同时,对制备的Au掺杂In_2O_3气体传感器的气敏特性进行了研究,实验结果表明,在最佳工作温度(250℃)条件下,3%(摩尔分数)Au掺杂In_2O_3气体传感器对100×10-6丙酮气体的灵敏度达到23.1,响应时间和恢复时间分别为10和13s。最后对Au掺杂In_2O_3的气敏机理进行了分析。     

NASICON固体电解质SO2传感器的特性研究

采用溶胶-凝胶法合成NASICON固体电解质材料,并以其为基体材料制作管式SO2传感器,敏感电极采用Na2SO3-30?SO4或者Na2SO4-30?SO4(摩尔比)复合硫酸盐.SO2浓度在(10～100)×10-6体积分数范围内,两种器件的灵敏度分别为81.1和60.6mV/decade.敏感电极为Na2SO3-30?SO4的元件响应和恢复时间分别为28.2 s和57.7 s;敏感电极为Na2SO4-30?SO4的元件响应和恢复时间分别为39.8 s和67.4 s.     

基于SnO2薄膜气体传感器的设计与制作（英文）

设计了一种带硅岛结构的基于SnO2薄膜材料的共面式气体传感器.利用有限元工具对传感器进行了稳态热分析,分析结果表明这种传感器在33.84 mW的功耗下最高温度达到400℃,气敏薄膜上温度分布均匀.详细阐述了传感器的制作过程,过程中总共使用4块掩模版用于光刻工艺.采用溶胶-凝胶法制备了SnO2纳米薄膜作为传感器的气敏元件.对传感器进行了气敏测试,实验结果表明该传感器拥有良好的气敏性能,在300℃下对50×10-6到2 000×10-6氢气的灵敏度逐渐递增,反应时间可控制在10 s以内.     

少量氧化锡掺杂提高三氧化钨探测H2S气体的气敏性能

为改善WO3基敏感材料的气敏性能,先采用液相还原法制备得到WO3粉体,再通过微波辅助液相法制备了SnO2掺杂量为0.5%、1%、3%、5%、10%(质量分数,下同)的SnO2-WO3复合材料。采用XRD和SEM对材料的物相、形貌进行了表征,并研究了掺杂SnO2对WO3气敏性能的影响。结果表明,掺杂3%的SnO2可显著提高WO3对H2S的灵敏度和选择性,在工作温度为160℃时,元件对体积浓度为10×10-6 H2S的灵敏度达65,对体积浓度为50×10-6 H2S的灵敏度高达169,且灵敏度与气体浓度呈现良好的线性关系。此外,纯WO3和SnO2(3%)-WO3材料在相对湿度RH=22%～64%时有良好的抗湿性。     

基于纳米CuO敏感电极混合位型NO2传感器的研究

采用溅射法制备的纳米结构CuO为敏感电极,钇稳定氧化锆(YSZ)为固体电解质制成了一种混合位型NO2传感器。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)分别表征了CuO敏感电极的相组成和微观形貌。研究了Cu的不同溅射时间对CuO敏感电极微观结构及传感器敏感性能的影响。结果表明,CuO颗粒随着Cu溅射时间的增长而增大,制成的传感器在600～700℃范围内对25～400mL/m3的NO2具有较好的敏感性能,传感器响应信号与NO2浓度的对数呈现良好的线性关系,其中60min,Cu传感器在650℃时灵敏度达41.47mV/decade,对于400mL/m3的NO2,90%的响应时间和恢复时间分别约为160、260s,体积分数0～10%的CO2对传感器的响应几乎没有影响,传感器具有较好的敏感度、重现性和稳定性。     

Post treatment of plasma-polymerized SnOx organic-like films with poly ethylene glycol for improving CO gas sensitivity

In this study, a new room temperature type gas sensor device based on plasma deposition of tetramethyltin (TMT) and O2 organically hybridized film followed by post treatment on the deposited film was developed for improving CO gas sensitivity and distinguishing from methane, butane, and carbon monoxide gases in the test environment. Plasma deposited SnOx thin film was first produced from TMT and O2 gas mixtures at room temperature, and then post treatments on the SnOx thin films were carried out by either spin coating with poly ethylene glycol (PEG) or surface grafting with p-styrenesulfonic acid sodium salt (Nass). It was found that the gas sensor spin coating post treated with PEG exhibits linear response to CO gas with the sensitivity not affected by methane and butane gases. For CO concentrations ranging from 30 to 650 ppm, steep change in the sensor resistance can be detected without warming up the sensor.     

基于气动加热原理的火星大气密度传感器可行性研究

火星大气密度测量需要传感器灵敏度高、功耗低、响应时间短,为此提出了基于气动加热原理的新型传感器方案。通过对火星轨道气体流动状态进行判断、对分子与热敏器件碰撞产生的热功率密度和正压强的计算和对噪声及性能的分析,新型传感器可行性从理论上得到了论证。传感器测量火星轨道高度范围为90 km到400 km,理论热响应时间为122 ms,最小可探测压强为2.05×10-8Pa。     

Model and Experimental Characterization of the Dynamic Behavior of Low-Power Carbon Monoxide MOX Sensors Operated With Pulsed Temperature Profiles

Wireless sensor networks for home automation or environment monitoring require low-cost low-power sensors. Carbon monoxide (CO) metal-oxide (MOX) sensors could be suitable in terms of device cost, but they show some severe limits, such as the need to be heated, which means large power consumption and the need for complex and frequent calibration procedures, which increases the overall cost. This paper investigates the possibility to partially overcome these limits by a low-cost detection system based on a suitable commercial sensor (TGS 2442, Figaro, Inc.) and an ad hoc measurement technique exploiting specifically tailored temperature profiles. To this aim, the authors study the dynamic behavior of low-power CO MOX sensors operated with pulsed temperature profiles by means of two approaches: 1) sensor modeling and 2) experimental evaluation. To analyze how the sensor dynamic response changes as a function of the CO concentration, the authors individuate a temperature profile, which ensures satisfactory sensitivity to the target gas and very low power consumption. Moreover, some parameters describing the sensor response shape are selected, which prove to be significant in terms of both robustness to environmental conditions and calibration simplicity.     

Carbon dioxide gas sensor based on ionic liquid-induced electrochemiluminescence

Electrochemiluminescence of the luminol-O(2) system in an electrolyte-free N,N-dimethylformamide (DMF)-dipropylamine (DPA) cosolution is induced by the formation of a carbamate ionic liquid (IL) from the reaction between CO(2) and DPA, on the basis of which a facile ECL sensor for measuring atmospheric CO(2) has been developed. This ECL sensing method shows several advantages in the detection of CO(2), such as high safety, high selectivity, wide linear response range, and good sensitivity. The gas sensor was found to have a linear response range from 100 ppm to 100 v/v% and a detection limit of 80 ppm (at signal-to-noise ratio of 3). This is the first reported IL-induced ECL sensor for a gas, thus the principle of this type of sensor and the IL-induced ECL mechanism have been demonstrated in detail.     

The effect of carbon nanotube dispersion on CO gas sensing characteristics of polyaniline gas sensor

Polyaniline is one of the most promising conducting polymers for gas sensing applications due to its relatively high stability and n or p type doping capability. However, the conventionally doped polyaniline still exhibits relatively high resistivity, which causes difficulty in gas sensing measurement. In this work, the effect of carbon nanotube (CNT) dispersion on CO gas sensing characteristics of polyaniline gas sensor is studied. The carbon nanotube was synthesized by Chemical Vapor Deposition (CVD) using acetylene and argon gases at 600 degrees C. The Maleic acid doped Emeradine based polyaniline was synthesized by chemical polymerization of aniline. CNT was then added and dispersed in the solution by ultrasonication and deposited on to interdigitated AI electrode by solvent casting. The sensors were tested for CO sensing at room temperature with CO concentrations in the range of 100-1000 ppm. It was found that the gas sensing characteristics of polyaniline based gas sensor were considerably improved with the inclusion of CNT in polyaniline. The sensitivity was increased and response/recovery times were reduced by more than the factor of 2. The results, therefore, suggest that the inclusion of CNT in MA-doped polyaniline is a promising method for achieving a conductive polymer gas sensor with good sensitivity, fast response, low-concentration detection and room-operating-temperature capability.     

Ag掺杂对ZnO纳米线气敏性能的影响

以采用物理热蒸发法制备的纯ZnO纳米线和Ag掺杂ZnO纳米线为气敏基料，制备成旁热式气敏元件，用静态配气法对浓度均为100ppm的无水乙醇蒸汽、氨气、甲烷及一氧化碳四种气体进行气敏性能测试，结果表明，Ag掺杂后，ZnO纳米线对四种气体灵敏度的最高值分别提高了230％，92％，158％，49％，缩短了响应时间和恢复时间。     

基于信息融合的矿井一氧化碳检测方法的研究

电化学传感器在检测矿井一氧化碳含量时，容易受到矿井中甲烷气体的影响。为了解决这个问题，将催化传感器与电化学传感器构成一体，利用两个传感器的输出信号，经过BP神经网络的训练，得到了一个分析一氧化碳的信息融合数学模型。实验表明，利用研究的信息融合信号处理方法，可以提高一氧化碳含量检测的可靠性。     

Adsorption of formaldehyde molecule on the intrinsic and Al-doped graphene: A first principle study

To search for a high sensitivity sensor for formaldehyde (H₂CO), we investigated the adsorption of H₂CO on the intrinsic and Al-doped graphene sheets using density functional theory (DFT) calculations. Compared with the intrinsic graphene, the Al-doped graphene system has high binding energy value and short connecting distance, which are caused by the chemisorption of H₂CO molecule. Furthermore, the density of states (DOS) results show that orbital hybridization could be seen between H₂CO and Al-doped graphene sheet, while there is no evidence for hybridization between the H₂CO molecule and the intrinsic graphene sheet. Therefore, Al-doped graphene is expected to be a novel chemical sensor for H₂CO gas. We hope our calculations are useful for the application of graphene in chemical sensor.     

Study on the micro-heater geometry in In,2O3 micro electro mechanical systems gas sensor platforms and effects on NO2 gas detecting performances

Micro electro mechanical systems (MEMS) platforms for gas sensing devices with the co-planar type micro-heaters were designed, fabricated and its effects on the In2O3 gas sensors were investigated. Micro-heaters in MEMS gas sensor platforms were designed in the four-type heater patterns with different geometries. Electro-thermal characterizations showed that the designed platforms had highly thermal efficiency because the micro hot-plate structures were formed in the diaphragm and the thermal efficiencies were analyzed for all of 16 models and compared with each other, respectively. The designed micro-platforms were fabricated by MEMS process, and Indium oxide (In2O3) nanoparticles were synthesized by sol-gel process and dropped on the MEMS platforms for detecting the noxious oxide gas (NO2) Fabricated micro-platforms had a very low power consumption in the fabricated 16-type models, especially, the minimum power consumption was 41 mW at the operating temperature of 250 degrees C. After experiments on gas sensing characteristics to NO2 gases, fabricated In2O3 gas sensors had almost the same gas sensitivity (Rs) at the operation temperature of 250 degrees C. It is concluded that the micro-heater geometries, pattern shapes and sizes, can be influential on the power consumption of the devices and its gas sensing characteristics.