高分子感湿膜的感湿特性

以国产材料(A)和日本进口材料(B)合成的高分子材料作感湿膜,制作了高分子湿敏器件,均具有良好的感湿特性。增涂乙基纤维素保护膜,有使(A)器件湿滞回差变大,(B)器件湿滞回差变小的趋势。浸水时间不当均可使两种器件的湿滞回差变大,因此合理控制浸水时间是必要的。     

半导体湿敏器件及其应用

大气中含水汽的多少.常用湿度来表示。要控制湿度,就要对湿度进行检测,关键元件就是湿敏器件。湿敏器件的性能指标有湿度量程、灵敏度、温度系数、响应时间、湿滞回差、感湿特征量——相对湿度特性曲线等。例如作为湿敏器件之一的湿敏半导体陶瓷,按其阻值随环境湿度的变化规律,又可分为两大类:负感湿特性的半导体陶瓷。其阻值随环境湿度的增加而减小;正感湿特性的半导体陶瓷,其阻值随环境湿度的增加而增加。从结构上分,又可分为烧结型、涂覆膜型、多孔氧化物型、结型和MOS型半导体湿敏器件等。湿敏器件的应用是一种非电物理量的电气测量。湿敏电阻即其中的一种。它在一定的电源驱动下,将湿度量转换成电量,然后直接通过仪表读出或调节控湿     

石英谐振式湿敏元件的研制

在一定规格的石英晶片两侧利用蒸发、溅射方法形成Ａｕ膜作电极和引线。在金膜的中间部分涂覆面积适当的高分子湿敏膜材料 ,即可制成石英谐振式湿敏器件。以疏水性的甲基丙烯酸丁酯 (Ｂｕ)和亲水性的丙烯酸羟乙酯的氯胺盐 (Ｑｂ)聚合成的高分子材料为敏感膜 ,为增加强度 ,在合成过程中加入一定量的交联剂丙烯酸羟乙酯 (Ｑｃ) ,三者的最佳配比通过实验加以选择。Ｂｕ∶Ｑｂ =7∶3时 ,器件具有良好的感湿特性 ,不仅感湿范围宽 ,灵敏度高 ,而且湿滞回差很小 ,只有 2 %ＲＨ。Ｂｕ∶Ｑｂ∶Ｑｃ =5∶2∶3时 ,制作的器件虽然灵敏度也高 ,但湿滞回差…     

结构参数对Ba1-xLaxTiO3多功能传感器敏感特性的影响

对三种二氧化硅层厚度 (1 0 nm、2 5 nm、40 nm)的器件进行测试 ,研究二氧化硅层的厚度对 Ba1 - x Lax Ti O3多功能传感器敏感特性的影响。结果表明 ,对于 MIS电容传感器 ,氧化层越薄 ,湿敏灵敏度越高 ,湿滞越小 ;相反 ,对于薄膜电阻传感器 ,氧化层越厚 ,光敏灵敏度越高。总之 ,选择一个合适的氧化层厚度 ,器件可以同时具有较高的湿敏、光敏灵敏度。     

半导体湿敏器件及其应用

介绍了半导体湿敏器件的基本分类和性能，提出了应用湿敏器件的应注意的有关问题，详述了三种实用测湿，控湿电路。     

ZrO_2/聚苯乙烯磺酸钠复合湿敏元件的性能研究

从高度分散的ZrO2溶胶出发,制备了ZrO2/聚苯乙烯磺酸钠(NaPSS)有机-无机复合湿敏元件,研究了NaPSS掺入量对湿敏元件性能的影响,并采用复阻抗谱分析了湿敏元件的感湿机理。结果表明:加入适量的NaPSS有利于改善湿敏元件的灵敏度和线性,当NaPSS与ZrO2的质量比为1:100时,所制复合湿敏元件的性能最好,其湿滞小(2%RH),响应-恢复时间短(吸附时间:2 s,脱附时间:15 s);复阻抗谱分析说明湿敏元件对湿度的电响应经历了一个从低湿下的电荷转移到高湿下的离子扩散导电的过程。     

西门子推出了附带湿敏器件解决方案的软件SIPLACE Setup Center V3．0

随着电子制造技术的不断发展,电子元器件的体积正变得越来越小,同时在整个供应链中有效管理并保护湿敏器件,对于电子制造商来说也正变得越来越重要。而管理和保护湿敏器件的目的就是为了避免从表面贴装的起始阶段就使用受到潮湿损坏的器件。     

复合钒钛酸干凝胶薄膜的湿敏特性研究

采用sol-gel法制备了复合钒钛酸干凝胶(H2V10Ti2O30-y·nH2O)薄膜,并对其湿敏特性进行了研究。结果表明:该薄膜为层状结构。用此薄膜制备的湿敏元件,在RH为11%～95%的范围内,感湿特性曲线线性好,其响应、恢复时间分别为5s和20s,湿滞为RH2%,感湿温度系数为RH0.45%/℃,并具有良好的稳定性。H2V10Ti2O30-y·nH2O干凝胶薄膜湿敏元件的灵敏度和湿滞均优于复合钒酸(H2V12O31-y·nH2O)干凝胶薄膜湿敏元件。     

SnO_2-LiZnVO_4系湿敏元件电容特性分析

采用共沉淀法制备SnO2-LiZnVO4系湿敏材料,研究了LiZnVO4的掺杂量对材料湿敏电容的影响。结果表明:LiZnVO4的掺杂量,环境的相对湿度(RH)、测试信号频率对湿敏电容有较大影响。当x(LiZnVO4)为10%时,可使材料具有合适的低湿电容和灵敏度。在100Hz下,当环境的RH从33%上升到93%时,SnO2-LiZnVO4系湿敏材料制备的湿敏元件的电容增量可达起始值的2300%,显示出较高的电容湿度敏感性。湿敏元件的电容响应时间约为54s,恢复时间约为60s。湿滞约为RH6%。     

K+掺杂对SnO2-LiZnVO4系湿敏陶瓷性能的影响

为了提高 SnO_2-LiZnVO_4系湿敏材料的性能,采用共沉淀法制备出 SnO_2-K_2O-LiZnVO_4系纳米湿敏粉体。考察了液相掺杂 K+对材料湿敏性能、复阻抗特性和电容特性的影响。实验结果表明,采用共沉淀法制备纳米粉体并使K+液相掺杂量为 2.5%(摩尔分数),可使湿敏材料低湿电阻小、灵敏度适中,适当的 K+添加量可明显改善 SnO_2-LiZnVO_4系纳米材料的感湿特性。     

Biocompatible Soft Fluidic Strain and Force Sensors for Wearable Devices

Fluidic soft sensors have been widely used in wearable devices for human motion capturing. However, thus far, the biocompatibility of the conductive liquid, the linearity of the sensing signal, and the hysteresis between the loading and release processes have limited the sensing quality as well as the applications of these sensors. In this paper, silicone based strain and force sensors composed of a novel biocompatible conductive liquid (potassium iodide and glycerol solution) are introduced. The strain sensors exhibit negligible hysteresis up to 5 Hz, with a gauge factor of 2.2 at 1 Hz. The force sensors feature a novel multifunctional layered structure, with microcylinder‐filled channels to achieve high linearity, low hysteresis (5.3% hysteresis at 1 Hz), and good sensitivity (100% resistance increase at a 5 N load). The sensors' gauge factors are stable at various temperatures and humidity levels. These biocompatible, low hysteresis, and high linearity sensors are promising for safe and reliable diagnostic devices, wearable motion capture, and compliant human–computer interfaces.     

Perovskite‐Induced Ultrasensitive and Highly Stable Humidity Sensor Systems Prepared by Aerosol Deposition at Room Temperature

A new capacitive‐type humidity sensor is proposed using novel materials and fabrication process for practical applications in sensitive environments and cost‐effective functional devices that require ultrasensing performances. Metal halide perovskites (CsPbBr₃ and CsPb₂Br₅) combined with diverse ceramics (Al₂O₃, TiO₂, and BaTiO₃) are selected as sensing materials for the first time, and nanocomposite powders are deposited by aerosol deposition (AD) process. A state‐of‐the‐art CsPb₂Br₅/BaTiO₃ nanocomposite humidity sensor prepared by AD process exhibits a significant increase in humidity sensing compared with CsPbBr₃/Al₂O₃ and CsPbBr₃/TiO₂ sensors. An outstanding humidity sensitivity (21426 pF RH%^?1) with superior linearity (0.991), fast response/recovery time (5 s), low hysteresis of 1.7%, and excellent stability in a wide range of relative humidity is obtained owing to a highly porous structure, effective charge separation, and water‐resistant characteristics of CsPb₂Br₅. Notably, this unprecedented result is obtained via a simple one‐step AD process within a few minutes at room temperature without any auxiliary treatment. The synergetic combination of AD technique and perovskite‐based nanocomposite can be potentially applied toward the development of multifunctional sensing devices.     

A Perylene Bisimide‐Contained Molecular Dyad with High‐Efficient Charge Separation: Switchability,Tunability, and Applicability in Moisture Detection

Designing novel fluorophores with nonplanar structure and environmental sensitivity is of great significance for the development of high‐performance film‐based fluorescent sensors. Herein, a unique pentiptycene (P) and perylene bisimide (PBI)‐contained fluorescent dyad (P‐PBI‐P) displaying a switchable and tunable charge separated state is reported. It is demonstrated that this symmetrical and dumbbell‐like molecular dyad shows a greater extent of photoinduced intramolecular electron transfer than the asymmetrical dyad, P‐PBI. In addition, the charge separated state (P⁺‐PBI^?‐P/P‐PBI^?‐P⁺) of the fluorophore is super susceptive to solvent polarity, allowing sensitive detection of water content in organic liquids. Based on the finding, two P‐PBI‐P‐based fluorescent humidity sensors are fabricated, and they both show linear responses to air humidity within a range of at least 6.3% to 100% (relative humidity, RH). The response time is less than a few seconds, and the recovery time less than 1 min. Importantly, almost no hysteresis is found during a cyclic humidification and dehumidification test within the whole RH range studied. The superior performance of the humidity sensors based on the modulation of the charge separated state of a fluorophore constitutes an effective way for designing high‐performance film‐based fluorescent sensors.     

Organic field-effect transistors as high performance humidity sensors with rapid response,recovery time and remarkable ambient stability

The stability of organic field-effect transistors (OFETs) under very high humidity condition has been the bottleneck in many applications. In this work, remarkable enhancement in ambient stability and performance of CuPc based OFETs are observed by exploiting the polarization of hydroxyl groups in Poly (vinyl alcohol) (PVA) dielectric layer, which is sandwiched between Al₂O₃ and Poly (methyl methacrylate) (PMMA) layer. The devices are used to fabricate OFETs based humidity sensors, which show exceptional ambient stability and rapid response to the water molecules in moisture. In a controlled experiment, the sensors demonstrate 0.73 s as response time and 0.52 s as recovery time. Such results are the fastest responses observed on humidity sensors fabricated based on OFETs. The enhanced responses of the sensors are due to the systematic polarization of the hydroxyl groups present in PVA layer by the additional dipole field arising from the adsorbed water molecules, which are also polarized under gate-field. The devices show no variation in threshold voltage as well as field-effect carrier mobility, measured throughout a year under ambient exposure. The specific design of the sensors with tri-layer dielectric system plays crucial role in enhancing the stability and moisture sensitivity, which can make the devices technologically very relevant.     

一种格栅状上电极的CMOS工艺聚酰亚胺电容型湿度传感器

报道了采用标准CMOS工艺制作的格栅型上电极的电容型湿度传感器,采用高分子材料聚酰亚胺作为感湿介质,铝作为金属电极.对该湿度传感器的器件结构、制作工艺和传感器特性,如灵敏度、湿滞以及响应时间等进行了讨论.测试结果表明,在12%～92%的湿度范围内,电容一相对湿度曲线具有良好的线性度,灵敏度为0.9 pF/RH,响应时间...     

纺织基底无芯片RFID 湿度传感器

研制了一种无湿敏材料的纺织基底无芯片RFID 湿度传感器用于检测环境湿度。通过射频仿真软件 HFSS,获得谐振频率在2. 45 GHz 具有较高品质因数的纺织基底谐振器模型,对以谐振频率偏移量作为灵敏度指标 的检测原理进行了仿真。利用丝网印刷工艺和刻绘工艺分别在不同类型纺织物上制作了无芯片RFID 湿度传感器, 系统研究了制作工艺、纺织品类型和厚度对传感器湿敏特性的影响。结果表明,0. 5 mm 厚度下不同基底类型湿度传 感器的灵敏度由高至低依次为:棉基底、亚麻基底、聚酯纤维基底,恢复特性呈相反顺序,其中棉基底传感器在高湿 范围内平均灵敏度达3. 8 MHz/ %RH,聚酯纤维基底传感器恢复度达86%;相同类型的棉纺织基底下基底厚度越大, 平均湿度灵敏度越高,恢复特性越差。传感器稳定性测试表明传感器具有较好的中长期稳定性。对纺织基底湿度 传感器的感湿机理进行了分析,纺织纤维中的亲水基团与水分子间形成氢键,改变了基底的介电参数,传感器的湿 敏特性与组成纺织品的纤维成分、纤维细度、编织方式有关。     

Humidity-Initiated Gas Sensors for Volatile Organic Compounds Sensing

A new volatile organic compounds (VOCs) sensing concept called humidity-initiated gas (HIG) sensors is described and demonstrated. HIG sensors employ the impedance of water assembled at sensor interfaces when exposed to humidity to sense VOCs at low concentrations. Here, two HIG sensor variants are studied—Type I and Type II. Type I sensors benefit from simplicity, but are less attractive in terms of key performance metrics, including response time and detection limits. Type II sensors are more complex, but are more attractive in terms of key performance metrics. Notably, it is observed that the best-in-class Type II HIG sensors achieve <2 min response times and <10 ppb detection limit for geranyl acetone, a VOC linked to the asymptomatic form of Huanglongbing (HLB) citrus disease. Both Type I and Type II sensors are assembled from off-the-shelf materials and demonstrate remarkable stability at high humidity. HIG sensors are proposed as an attractive alternative to existing VOCs sensors for remote field detection tasks, including VOCs detection to diagnose HLB citrus disease.     

复合钒钼酸干凝胶薄膜湿敏特性的影响因素

采用sol-gel法制备复合钒钼酸H2V12–xMoxO31±y·nH2O(0≤x≤4)干凝胶薄膜并研究了Mo含量、电极及温度等对其湿敏特性的影响。结果表明:当工作频率为1kHz,温度20℃,涂覆于金电极上的H2V10Mo2O31±y·nH2O(x=2)干凝胶薄膜在全湿度范围内具有线性好、灵敏度较高、响应快、湿滞小的特点,是一种很有前途的新型湿敏材料。