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Reduction and compensation of humidity measurement errors at cold temperatures using dual QCM humidity sensors based on graphene oxides
摘要： One of the difficulties in measurements of relative humidity in a variety of environments is temperature-dependence especially at cold temperatures. Here, we report on the reduction and the compensation of temperature effects on humidity measurements using dual humidity sensors based on quartz crystal microbalance (QCM). Graphene oxide film is coated on quartz crystals as a humidity sensing layer for the detection of water sorption by the change of resonance frequency. Relative humidity in a test chamber, where dual QCM humidity sensors are located, is precisely controlled using a humidity generator at the temperature range from 20 °C to ?60 °C. It is found that single QCM humidity sensors measure humidity significantly higher than reference relative humidity by the generator as temperature is lowered due to the temperature-dependent resonance of quartz crystals. In an attempt to cancel out the temperature-dependent oscillation of QCM sensors, the ratio of resonance frequencies of dual QCM humidity sensors is used. Consequently, temperature-dependent errors in humidity measurement at low temperatures are evidently reduced. For the compensation of the remaining errors in the humidity measurement by dual QCM humidity sensors, a single formula is empirically obtained. After the compensation of low temperature effects, the dual QCM humidity sensors provide the measurement capability in terms of residual errors less than 1.1%rh throughout temperatures from 20 °C to ?60 °C. This study provides a useful insight to extend the applicability of QCM-based humidity sensors to environments with cold temperatures.
关键词： Compensation,Graphene oxide,Cold temperature,Quartz crystal microbalance,Humidity measurement,Humidity sensor
更新于2025-09-23 15:23:52
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Highly Responsive PEG/Gold Nanoparticle Thin Film Humidity Sensor via Inkjet Printing Technology
摘要： In this study, a highly responsive humidity sensor is developed by printing gold nanoparticles (GNP) grafted with a hygroscopic polymer. These GNPs are inkjet printed to form a uniform thin film over an interdigitated electrode with controllable thickness by adjusting the printing parameters. The resistance of the printed GNP thin film decreases significantly upon exposure to water vapor and exhibits a semi-log relationship with relative humidity (RH). The sensor can detect RH variations from 1.8% to 95% with large resistance changes up to 4 order of magnitude with no hysteresis and small temperature dependence. In addition, with a thin thickness, the sensor can reach absorption equilibrium quickly with response and recovery times of ≤1.2 and ≤3 seconds, respectively. The fast response to humidity changes also allows the GNP thin film sensor to distinguish signals from intermittent humidification/dehumidification cycles with a frequency up to 2.5 Hz. The printed sensors on flexible substrates show little sensitivity to bending deformation and can be embedded in a mask for human respiratory detection. In summary, this study demonstrates the feasibility of applying printing technology for the fabrication of thin film humidity sensors, and the developed methodology can be further applied to fabricate many other types of nanoparticle based sensor devices.
关键词： inkjet printing,respiratory monitoring,Humidity sensor,gold nanoparticle,poly(ethylene glycol)
更新于2025-09-23 15:23:52
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All-optical graphene-oxide humidity sensor based on a side-polished symmetrical twin-core fiber Michelson interferometer
摘要： A high-sensitive graphene-oxide (GO) humidity sensor based on a side-polished twin-core fiber (SPTCF) Michelson interferometer (MI) has been demonstrated. The MI was fabricated by splicing a section of TCF to a standard single mode fiber (SMF) and tapering the splicing point. The exposed polished core has a stronger evanescent field and enhances the interaction between light and external environment. The GO-SPTCFMI can operate in the wavelength- and intensity- modulated sensor. The super-high humidity sensitivities of ~2.72 nm/RH% in the RH range of 40-75% and ~3.76 dB/RH% in the RH range of 60-62.1% are obtained experimentally. The high-performance GO-SPTCFMI is a promising candidate for potential applications, such as gas sensing and biochemical detection.
关键词： side-polished fiber,graphene oxide,Humidity sensor,twin core fiber,interferometer.
更新于2025-09-23 15:23:52
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Effect of Different Inorganics on Polyimide-based Bragg Grating Humidity Sensor
摘要： Effect of activated carbon and lithium chloride on polyimide-based fiber Bragg Grating relative humidity sensor has been experimentally investigated. Through dip coating process, organic-inorganic hybrid coatings were deposited on fiber Bragg grating to form different relative humidity sensors. Experimental results show that the addition of activated carbon or lithium chloride alone could increase the humidity sensitivity (1.67 times and 1.61 times, respectively), but the structure which contains both lithium chloride and activated carbon increases the sensitivity most (3.9 times). In the 14-day stability test, the fluctuation of pure polyimide sensor is ± 6.5%, while the ones of activated carbon sensor, lithium chloride sensor, activated carbon and lithium chloride sensor are ± 3%, ± 8%, and ± 1.6%.
关键词： lithium chloride,fiber Bragg grating,activated carbon,polyimide,humidity sensor
更新于2025-09-23 15:22:29
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Humidity sensing properties of metal organic framework-derived hollow ball-like TiO2 coated QCM sensor
摘要： This paper demonstrates three kinds of TiO2 with hollow ball, nanosphere, and nanoflower nanostructures coated quartz crystal microbalance (QCM) humidity sensors, which were synthesized by metal organic framework (MOF)-derived, hydrothermal and solvothermal route, respectively. The compositional and morphological characteristics of three kinds of TiO2 nanostructures were characterized by means of X-ray diffraction (XRD), specific surface area analysis (BET), scanning electron microscopy (SEM) and water contact angle measurement. We found that the surface structure plays a crucial role in the humidity-sensing response properties of QCM sensors. The humidity sensing experiment was performed at room temperature. The MOF-derived hollow ball-like TiO2 coated QCM sensor exhibited excellent humidity sensing characteristics over a wide RH range (0%-97%RH), such as high sensitivity (33.8 Hz/%RH), good repeatability and short dynamic response/recovery times (5 s/2 s). In addition, Langmuir adsorption model was developed to explain the humidity-sensing properties of the TiO2-based QCM sensor. This work proves that MOF-derived hollow-ball TiO2 is a potential candidate nanomaterial for humidity sensor fabrication.
关键词： humidity sensor,Langmuir adsorption model,quartz crystal microbalance,hollow ball-like TiO2
更新于2025-09-23 15:22:29
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The Size Effect of Exfoliated MoS <sub/>2</sub> Based Thin Film Humidity Sensor
摘要： Layered two-dimensional nanomaterials such as MoS2 show great potential for sensor application owing to their distinct nature that most atoms are surface atoms. The difficult in mass production of exfoliated MoS2 hinders its practical application. In this study, we investigate the ultrasound assisted liquid method to efficiently exfoliate MoS2 into nanosheets and nanoparticles. The dependence of ultrasonic dosing, e.g., ultrasonic time, on the morphology and yield of final products are studied. The exfoliated MoS2 nanomaterials are fabricated into thin film sensors and examined with humidity gas. The sensors exhibit excellent and quick response toward humidity gas. We find the sensor prepared with longer ultrasonic treatment presents higher response owing to that the longer ultrasonic irradiation exposes more active edge sites.
关键词： Exfoliation,Humidity Sensor,MoS2,Size Effect,Thin Film
更新于2025-09-23 15:22:29
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Investigations on Synthesis, Characterization and Humidity Sensing Properties of ZnO and ZnO-ZrO2 Composite Nanoparticles Prepared by Ultrasonic Assisted Wet Chemical Method
摘要： In the present investigations, Zinc oxide (ZnO) and ZnO-ZrO2 composite nanoparticles were synthesized by ultrasonic assisted wet chemical method to investigate their structural, optical and humidity sensing properties. The synthesized nanoparticles were characterized by the techniques like X ray diffraction (XRD), UV-Vis absorption spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). XRD and EDS were employed to confirm the phase formation and phase purity respectively. SEM micrographs showed that morphology of the parent compound ZnO is considerably changed with varying concentration of ZrO2. The optical absorption spectra showed that optical absorption of ZnO decreases with increase in ZrO2 content in the composite. The observed band gap values for ZnO and ZnO-ZrO2 composites were higher as compared to the bulk sample. The humidity sensing performance was substantiated for all the samples and the result of effect of concentration of ZrO2 in ZnO-ZrO2 composites on sensitivity, response and recovery time are discussed in detail.
关键词： Zinc oxide,Composite nanoparticles,Zirconium dioxide,Ultrasonic,Humidity sensor
更新于2025-09-23 15:22:29
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EFFECT OF SIZE ON SINGLE AND DOUBLE OPTICAL MICROBOTTLE RESONATOR HUMIDITY SENSORS
摘要： An experimental study on the effect of whispering gallery mode (WGMs) on micro-bottle resonator (MBR) and its application on humidity sensing is presented. Different transmission mode spectra observed when the diameter of MBR (Db) change from 130μm to 190μm. The Q-factor for single and double MBRs ware observed > 104 for all cases. The size and number of MBRs effecting Q-factor value which are high Q-factor value for smallest size Db = 130μm for single MBR and Pair-4 (combination of two biggest MBRs Db = 190μm) for double MBRs. Application of single and double MBRs in humidity sensing received various sensing performance. With the highest sensitivity value, linearity >90% and P-value > 10-13 make MBR with diameter 130μm to be the best performance as humidity sensor for all cases. Both single and double MBRs are stable over 60 seconds. Overall, the size of the MBR has been shown to be more important than the quantity of MBRs for humidity sensing. Indeed, double MBRs actually perform worse than single MBRs as humidity sensors.
关键词： Q-factor,Sensitivity,Humidity sensor,Whispering gallery mode,Micro-bottle resonator
更新于2025-09-23 15:21:21
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Fast-response humidity sensor based on laser printing for respiration monitoring
摘要： Respiration monitoring equipment has wide applications in daily health monitoring and modern medical diagnosis. Despite significant progress being made in humidity sensors for respiration monitoring, the fabrication of the humidity sensors with low-cost, simple manufacturing process and easy integration remains a challenge. This work reports a facile and inexpensive laser printing fabrication of PEDOT:PSS micron line as a humidity sensor for respiration monitoring. Laser printing technology can process any material into an arbitrary pattern. The PEDOT:PSS micron line humidity sensor has a fast response–recovery time (0.86 s/0.59 s), demonstrating excellent performance for real-time monitoring of human respiration. Furthermore, the PEDOT:PSS micron line humidity sensor can also monitor the respiration of rats under different physiological conditions along with the drug injection. The PEDOT:PSS micron line humidity sensor features simple manufacturing process with commercial materials, and easy integration with wearable devices. This work paves an important step in real-time monitoring of human health and further physiology and pharmacology study.
关键词： respiration monitoring,laser printing,wearable devices,PEDOT:PSS,humidity sensor
更新于2025-09-23 15:19:57
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High-performance optical fiber humidity sensor based on lossy mode resonance using a nanostructured polyethylenimine and graphene oxide coating
摘要： In this study, a rapid optical fiber sensor for humidity with high sensitivity and wide detection range has been constructed, based on lossy mode resonance (LMR). A thin film made of alternating polyethylenimine (PEI) and graphene oxide (GO) layers was selected as sensitive coating. It was deposited on a SnO2-sputtered fiber core in a dip-assisted layer-by-layer assembly. The structure and surface chemistry of the raw materials were investigated by means of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Key properties such as sensitivity, linearity, hysteresis, stability and response and recovery times were characterized. The sensor exhibited excellent sensitivity, especially at high relative humidity (RH) levels, and short reaction and retrieval periods. This research provides a viable and practical way to fabricate high performance humidity optical fiber sensors with GO-based nanostructured coatings.
关键词： relative humidity sensor,layer-by-layer,breathing monitoring,graphene oxide,lossy mode resonance,Optical fiber sensor
更新于2025-09-19 17:15:36