基于硝化纳米纤维素/琼脂的高灵敏度湿度传感器

湿敏材料是决定湿度传感器性能的关键,本研究将具有特殊化学结构的纤维素和琼脂这两种生物质材料有机结合起来,制备具有不同湿度敏感性的硝化纳米纤维素/琼脂（nitrocellulose nanocrystals/Agar,NCNCs/Agar）复合敏感膜材料,基于石英晶体微天平（quartz crystal microbalance,QCM）制备出具有高灵敏度的湿度传感器。结果表明,NCNCs/Agar复合敏感膜修饰的QCM湿度传感器的灵敏度和频率响应值较单一材料敏感膜修饰的QCM均有较明显的提高。经过优化测试,得到NCNCs与琼脂的最佳质量比为1∶25,涂覆2.049μg敏感材料的QCM传感器（QCM-b）性能最优异。在相对湿度（RH）11%~84%下,QCM-b具有良好的线性（R²=0.9933）,灵敏度为32.54Hz/%RH。在RH 11%~97%下,QCM-b响应值可达到-5820Hz,具有优异的对数拟合系数（R²=0.9994）,恢复时间短（5s）,并且具有良好的重现性和长期稳定性,显示出在湿度探测领域的良好应用前景。     

硼掺杂Co3O4海胆状微球的制备及其乙醇气敏强化机制

四氧化三钴（Co₃O₄）是一种p型半导体,可作为气体传感材料。非金属硼（B）具有吸电子特性,将其与p型半导体气敏材料进行掺杂,可增加材料的空穴载流子浓度,从而提高材料的气敏性能。本文以六水合硝酸钴[Co(NO₃)₂·6H₂O]、硼酸（H₃BO₃）和尿素[CO(NH₂)₂]为原料,采用低温一步水热法成功制备了B掺杂Co₃O₄海胆状微球。通过X射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）、X射线光电子能谱仪（XPS）和拉曼光谱仪（Raman）对掺杂B前后的Co₃O₄进行结构表征,探究B掺杂对其气敏性能的影响。结果表明：B掺杂对Co₃O₄材料的气敏性能有明显的强化作用。当掺杂摩尔比为Co∶B=8∶1时,B-Co₃O₄对1×10⁵μg/L乙醇的最佳工作温度为180℃,灵敏度响应达到26.8,是相同条件下纯Co₃O₄的4.4倍。B-Co₃O₄在较低的工作温度下,具有良好的灵敏度、选择性和稳定性,是一种性能优良的气敏材料。     

铜离子掺杂CsPbCl3量子点光学性能及稳定性探究

近年来,钙钛矿因其特殊的结构受到广泛的关注。其中,全无机钙钛矿量子点作为下一代发光材料更因其优异的发光性能得到了广泛的研究和关注。但是因为其本身的铅（Pb）元素带来的毒性和较差的稳定性,钙钛矿量子点在生产和应用方面依然面临着诸多阻碍。为了解决这些难题,介绍了一种铜离子（Cu²⁺）B位掺杂CsPbCl₃钙钛矿量子点。采用了热注射的方法成功地将Cu²⁺引入CsPbCl₃钙钛矿量子点中。研究发现,Cu²⁺掺杂CsPbCl₃量子点能够保持初始四方晶体结构。由于Cu²⁺的掺杂,有效地消除了CsPbCl₃量子点的表面缺陷,从而通过辐射途径促进了激子复合,提高了CsPbCl₃量子点的发光性质。通过稳定性对比测试发现,一段时间内,Cu²⁺掺杂CsPbCl₃量子点在水中的发光强度明显高于CsPbCl₃量子点。     

三元体系K +,Cs +//SO4 2——H2O 298.2 K稳定相平衡研究

采用等温溶解法开展了三元体系K ⁺,Cs ⁺//SO₄ ^2--H₂O 298.2 K稳定相平衡研究,测定了该体系溶解度、密度及折光率。结果表明,该三元体系在298.2 K下属于复杂体系,有固溶体（K,Cs）₂SO₄产生,且固溶体相区最大;其稳定相图包含3条单变量曲线、3个析出相区和2个共饱点;共饱点处对应的液相组成分别为w（K₂SO₄）=11.69%、w（Cs₂SO₄）=4.02%和w（K₂SO₄）=3.39%、w（Cs₂SO₄）=60.84%。平衡液相的密度和折光率随Cs₂SO₄含量的增大呈现递增的趋势。采用经验公式对平衡液相的折光率进行理论计算,计算值和实验值具有良好的一致性。     

基于自动控制的化工有害气体传感器优化研究

采用溶胶-凝胶法制备了钙钛矿铁氧体(YbFeO₃)。通过使用YbFeO₃作为传感电极，在900℃的烧结温度下制备自动化控制的电位丙酮传感器。并在350～500℃下测试了不同质量分数丙酮的响应信号。结果表明：随着化工厂工作温度从350℃升到500℃,响应和恢复率加快。在400℃的最佳工作温度下，浓度为4 mol/L的丙酮响应和恢复时间分别显著缩短至27 s和33 s。响应值与丙酮含量对数之间的线性关系证实了所制备的自动化控制传感器的混合电位机制。附有YbFeO₃的自动化传感器具有良好的丙酮选择性，对C₃H₈和CO₂的交叉敏感性小，并且还表现出良好的重现性和长期稳定性，表明使用YbFeO₃制备的自动化传感器具有丙酮泄漏预警的能力。     

硫源对双壳层NiCo2S4超级电容性能影响

通过自模板法,选用硫代乙酰胺（TAA）、硫脲（TU）分别作硫源制备双壳层NiCo₂S₄纳米材料。其中以TAA为硫源制备的NiCo₂S₄表现出高的比电容（2064F/g,当电流密度为0.5A/g时）,优异的倍率性能（1291F/g,当电流密度为20A/g时）和较好循环稳定性。由动力学机制分析可知,NiCo₂S₄-TAA表面控制电容和扩散控制电容较NiCo₂S₄-TU均有提升。通过实验分析可知,TAA作为硫源合成的NiCo₂S₄是由较小的次级颗粒聚集而成,这有利于电化学过程中电解质离子的扩散。由于较好的导电性能和离子扩散速率,NiCo₂S₄-TAA表现出优异的电化学性能。上述结果表明,在本实验条件下,TAA是制备NiCo₂S₄电容器电极材料的最佳硫源。     

基于氯化钴改性的纤维素纸比色湿度传感器

为了获得兼具良好湿敏响应和颜色可视性的湿度传感器,以纤维素滤纸（FP）和氯化钴（CoCl₂）为原料,滤纸为传感器的基底材料,氯化钴为感湿材料和颜色指示剂,通过简单的浸泡-干燥的方法制得CoCl₂/FP复合膜。采用扫描电子显微镜（SEM）、傅里叶红外光谱仪（FTIR）、X射线衍射仪（XRD）对复合膜进行一系列物理化学性能测试。结果表明,CoCl₂/FP复合膜上均匀地分布着氯（Cl）元素和钴（Co）元素,且滤纸和氯化钴之间主要发生的是物理变化。采用电化学工作站和电脑配色仪对CoCl₂/FP比色湿度传感器进行电流响应测试和可见光光谱测试。结果表明,在相对湿度（RH）为11%~98%的范围内,CoCl₂/FP比色湿度传感器具有明显的电流响应,电流变化超过1000倍。另外,从低湿度到高湿度,CoCl₂/FP比色湿度传感器呈现出由蓝色到红色的颜色变化,且这种颜色变化是可逆的。     

陈化过程对溴铅甲胺钙钛矿太阳能电池性能影响的研究

氧气氛下的器件陈化对钙钛矿光伏电池的性能有显著影响。本文研究了通过溶液法组装的溴铅甲胺(MAPbBr₃)电池的性能,其中致密的和介孔的Ti O₂作为电子传输层,Spiro-OMeTAD作为空穴传输层。将MAPbBr₃钙钛矿太阳能电池置于湿度<10%的氧气氛暗箱中不同时间,探究O₂对钙钛矿薄膜缺陷的钝化影响,并且采用瞬态光电压(TPV)技术分析陈化前后器件在不同光照时间下的离子迁移。结果表明,陈化处理后,基于MAPbBr₃的器件性能得到明显改善,光电转换效率从4.18%提高到6.73%。这种原因可能归结于钙钛矿材料的缺陷态密度降低,因为在黑暗条件下,O₂在MAPbBr₃钙钛矿太阳能电池中进行扩散,从而起到钝化缺陷的作用。     

制备方法对钙钛矿薄膜结构及形貌的影响

采用液相连续沉积法制备了有机/无机杂化钙钛矿（CH₃NH₃PbI₃,MAPbI₃）光吸收层,并研究了不同薄膜形貌、晶体结构和光吸收能力对钙钛矿太阳能电池性能的影响。结果表明：制备工艺对吸光层形貌和器件光电性能产生很大的影响。相对于分步浸渍法,分步旋涂法（分步旋涂无机相碘化铅PbI₂和有机相甲胺碘CH₃NH₃I前驱液）和气体辅助修复法（新制初始MAPbI₃薄膜在室温下置于甲胺气氛中）能有效改善薄膜形貌和平整度,获得覆盖完全的均匀钙钛矿吸光层。同时,进一步分析了初始MAPbI₃膜的形貌对气体修复法制备全覆盖平整钙钛矿薄膜的影响,发现初始钙钛矿膜的形貌对最终修复后的膜层形貌没有影响,这可能是因为不同初始MAPbI₃膜经甲胺气体处理后均形成一种"甲胺铅化碘-甲胺"（MAPbI₃·MA）的液态中间相,再经退火处理后均获得平整、致密的钙钛矿膜层,极大地提高了MAPbI₃的结晶度和薄膜均匀性,从而提高活性层的吸光率、光电流和电池效率。     

Au/UiO-66(Hf)纳米复合材料修饰电极电化学检测Cr（Ⅵ）的性能研究

采用溶剂热法和化学还原法制备出Au/UiO-66(Hf)纳米复合材料,再将该纳米复合材料修饰到玻碳电极上,运用线性扫描伏安法（LSV）实现了废水中Cr（Ⅵ）的有效检测。Au/UiO-66(Hf)/GCE传感器对质量浓度范围为100～1 000μg/L的Cr（Ⅵ）具有优异的线性响应,检测灵敏度为0.002 34μA·L/μg,最低检测限为18.76μg/L。同时,该传感器具有良好的稳定性与抗干扰性能,对实际电镀废水中Cr（Ⅵ）的检测回收率达105.03%。     

基于电纺NiI2/TPU纳米纤维膜的湿敏变色传感器的制备及性能

以热塑性聚氨酯(TPU)母粒、碘化镍为原料,通过静电纺丝法制备了基于碘化镍/热塑性聚氨酯(NiI2/TPU)纳米纤维膜,将NiI2/TPU纳米纤维膜贴合在聚酰亚胺(PI)基叉指电极上制得湿度传感器.对纳米纤维膜的表面形貌及微观结构进行了表征分析,并研究了该传感器基于颜色变化和电阻电容响应的湿度敏感特性.结果表明,由于碘化镍的颜色变化特性,随相对湿度(RH)从0增加到97％,NiI2/TPU纳米纤维膜显示了从橘红色到黄绿色的颜色转变.此外,该湿度传感器表现出快速的响应/回复时间(0.9 s/9.9 s)、较宽的湿度监测区间(0～97％RH)、较小的洄滞度(0.4％RH)以及优异的稳定性能(>30 d).     

Lead-free double perovskite halide fluorescent oxygen sensor with high stability

Oxygen sensors, using organic-inorganic and all-inorganic lead halide perovskites, have demonstrated huge advantages in operating temperature, responding time, and reversing oxygen content detection. Nevertheless, the toxicity and instability issues hinder their wide application. In this work, for the first time, we report a sensitive fluorescence oxygen detector based on lead-free double perovskite Cs₂AgBiBr₆ thin film. The sensor has a remarkable performance in terms of fast response time of ≈56 s, recovery time of ≈91 s, and a relatively low limit of detection (LOD) of 150 ppm. More importantly, the unencapsulated sensor still exhibits an obvious response at low oxygen concentrations after two-week storage in ambient, and the device also exhibits good humidity, light, and thermal stability. Consequently, the lead-free double perovskite (Cs₂AgBiBr₆) will be promising environmentally friendly material in developing reversible, sensitive, high-efficiency, and stable perovskite oxygen sensors.     

溶胶-凝胶法制备LiCl/SiO2-Al2O3纳米复合薄膜的湿敏特性

采用溶胶-凝胶工艺,将LiCl湿敏组元复合到SiO2-Al2O3玻璃先驱体中,用提拉法镀膜,经过适当的热处理,可以获得具有纳米结构和良好湿敏特性的LiCl/玻璃基薄膜.湿敏特性研究表明该类薄膜制得的传感器可在全湿范围内实现对湿度的测量.     

氧化石墨烯/钒钛酸复合材料的制备及湿敏性能研究

通过Hummers法制备氧化石墨后进行超声分散,得到分散均匀的氧化石墨烯(GO)分散液,物理复合滴涂制备氧化石墨烯/钒钛酸薄膜并对其感湿性能进行了研究,并通过交流与直流方法对其感湿机理进行了深入探究。结果表明:氧化石墨烯/钒钛酸复合膜的湿敏性能优于氧化石墨烯和钒钛酸单层膜,该湿敏薄膜的湿滞为8.3%RH,灵敏度变化2个数量级,响应时间为8 s,还原时间为10 s,曲线线性度良好。材料在低湿阶段主要表现为电子导电,中高湿阶段为电子导电和离子导电同时存在,高湿阶段主要表现为离子导电。     

Microstructure and Electrical Properties of MgAl2O4 Thin Films for Humidity Sensing

Active elements for humidity sensors based upon MgAl₂O₄ thin films or sintered pellets were investigated. Thin films were deposited on Si/SiO₂ substrates by radiofrequency (rf) sputtering. Sintered MgAl₂O₄ pellets were prepared by traditional ceramic processing. Scanning electron microscopy (SEM) analysis showed that the thin films were rather dense and homogeneous, made up of clustered particles of about 20–30 nm, while the pellets showed a wide pore-size distribution. X-ray photoelectron spectroscopy (XPS) demonstrated that the thin films have a stoichiometry close to that of MgAl₂O₄. Sintered MgAl₂O₄ is crystalline, while it is disordered in thin-film form. The presence of two different components of the Al 2 p peaks was correlated with the structural difference between pellets and thin films. The relationship between good film–substrate adhesive properties and the chemical composition at the interface was studied. The electrical properties of the sensing elements were studied at 40°C in environments at different relative humidity (RH) values between 2% and 95%, using ac impedance spectroscopy. MgAl₂O₄ thin films showed interesting characteristics in terms of their use in humidity-measurement devices. Resistance versus RH sensitivity values showed variations as high as 4 orders of magnitude in the RH range tested for thin films, and 5 orders of magnitude for pellets. The differences in the electrical behavior of MgAl₂O₄ pellets and thin films were correlated with their different microstructures.     

Functionalized multi‐wall carbon nanotubes/silicone rubber composite as capacitive humidity sensor

Functionalized multi‐wall carbon nanotubes (MWCNTs) treated by mixed acids have been used to develop a capacitive humidity sensor based on MWCNTs/silicone rubber (SR) composite film. The MWCNTs/SR composites were prepared through conventional solution processed method. The micrographs of MWCNTs/SR composites were observed by transmission electron microscopy (TEM) and scanning electron microscope. The FT‐IR spectra demonstrated the successfully grafting of ? OH groups on the treated MWCNTs. The sensing properties of the composite at different relative humidity (RH) and frequency were characterized and linear sensing responses of the MWCNTs/SR composites to RH were observed. The treated MWCNTs/SR composite film (Tr‐film) had higher sensitivity than that of the untreated MWCNTs/SR composite film (Un‐film). Experimental data indicate that the Tr‐film exhibits an excellent long‐term stability, small hysteresis, and fine reproducibility. The response and recovery time of the Tr‐film were 30 and 27 s, respectively. Thereby, such Tr‐film had potential applications as humidity sensors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40342.     

EIS study of the effect of high levels of SO2 on the corrosion of polyester-coated galvanised steel at different relative humidities

The effect of SO₂ on the degradation of polyester-coated galvanised steel at different relative humidities was investigated using electrochemical impedance spectroscopy. Measurements were performed on specimens which had been tested in an accelerated gaseous corrosion test. For this purpose the samples were subjected to SO₂ gas for 16 days in atmospheric test cells with adjusted relative humidity (RH) from 60 to 100%. Subsequently, the impedance response of the coated material was measured and evaluated. The results indicated that the coating performance varies with RH. Thus, under condensing conditions, the organic coating and galvanised layer was totally removed, the impedance response being interpreted as the formation of an iron sulphide film on the surface. At lower RH, remarkably, the coating remained effectively intact with the coating resistance varying inversely with RH. This work is relevant to the application of such organic-coated products adjacent to combustion flues where high levels of SO₂ occur in association with high humidity.     

A Novel Highly Sensitive Humidity Sensor Based on ZnO/SBA‐15 Hybrid Nanocomposite

This work deals with the study of hydrothermally synthesized zinc oxide (ZnO) loaded mesoporous SBA‐15 hybrid nanocomposite for relative humidity sensing (RH) at room temperature. The sensor exhibits an excellent ~5 orders impedance change along with excellent linearity, quick response time (17 s), rapid recovery time (18 s), negligible hysteresis (1.2%), good repeatability, and stability (1.8%) in 11%–98% RH range. In addition, complex impedance spectra of the sensor at different RHs were analyzed to understand the humidity sensing mechanism. Our study can open a new way for realizing ZnO/SBA‐15 hybrid nanocomposite for fabrication of high‐performance RH sensors.