To facilitate real-time monitoring and recording of humidity in the environment and to satisfy the requirement for strain performance in certain applications(such as wearable devices),this paper proposes an in-situ me...To facilitate real-time monitoring and recording of humidity in the environment and to satisfy the requirement for strain performance in certain applications(such as wearable devices),this paper proposes an in-situ method for synthesising Au nanoparticles on ZIF-67.In this study,an Au@ZIF-67 composite humidity-sensitive material was combined with flexible polyethylene terephthalate interdigitated electrodes to create an Au@ZIF-67 flexible humidity sensor.The prepared samples were characterised using X-ray diffraction,X-ray photoelectron spectroscopy,and transmission electron microscopy.The humidity-sensitive properties of the sensor were investigated,and its monitoring capabilities in applications involving respiration,gestures,skin,and baby diapers were tested.The experimental results indicate that compared with a pure ZIF-67 humidity sensor,the Au@ZIF-67(0.1Au@Z)flexible humidity sensor exhibits a 158.07%decrease in baseline resistance and a 51.66%increase in sensitivity to 95%relative humidity,and the hysteresis,response time,and recovery time are significantly reduced.Furthermore,the sensor exhibits excellent characteristics such as high resolution,repeatability,and stability.The obtained results regarding the material properties,humidity sensitivity,and practical application of non-contact humidity monitoring demonstrate that the prepared sensors exhibit excellent and comprehensive performance,indicating their broad prospects in wearable medical devices,wireless Internet of Things,humidity detection in complex environments,and intelligent integrated systems.展开更多
In order to solve the lack of relevant evaluation research on the accuracy of HMP155A humidity sensor calibration results in the past, this paper designs the corresponding experimental scheme, and obtains the correspo...In order to solve the lack of relevant evaluation research on the accuracy of HMP155A humidity sensor calibration results in the past, this paper designs the corresponding experimental scheme, and obtains the corresponding calibration results according to the experimental scheme;Then the measurement uncertainty of the indication error in the calibration results is evaluated by GUM, and the corresponding extended uncertainty </span><i><span style="font-family:Verdana;">U</span></i><sub><span style="font-family:Verdana;">95</span></sub><span style="font-family:Verdana;"> is obtained. Finally, according to the requirements of JJF1094-2016 characteristic evaluation of measuring instruments, combined with the calibration results and the actual situation of </span><i><span style="font-family:Verdana;">U</span></i><sub><span style="font-family:Verdana;">95</span></sub><span style="font-family:Verdana;">, the conformity of the indication error of calibration is determined. The result is that each calibration point of the sensor meets the requirements of conformity determination and is within the qualified range. This research effectively makes up for the blank of the previous research on the conformity determination of the indication error of the calibration results and has strong theoretical and practical significance.展开更多
Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to ...Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to avoid underlying risks,and for the early detection and treatment of diseases for home healthcare.Hydrogels with three-dimensional polymer networks and large amounts of water molecules are naturally flexible and stretchable.Functionalized hydrogels are intrinsically conductive,self-healing,self-adhesive,biocompatible,and room-temperature sensitive.Compared with traditional rigid vapor sensors,hydrogel-based gas and humidity sensors can directly fit human skin or clothing,and are more suitable for real-time monitoring of personal health and safety.In this review,current studies on hydrogel-based vapor sensors are investigated.The required properties and optimization methods of wearable hydrogel-based sensors are introduced.Subsequently,existing reports on the response mechanisms of hydrogel-based gas and humidity sensors are summarized.Related works on hydrogel-based vapor sensors for their application in personal health and safety monitoring are presented.Moreover,the potential of hydrogels in the field of vapor sensing is elucidated.Finally,the current research status,challenges,and future trends of hydrogel gas/humidity sensing are discussed.展开更多
Ti_(3)C_(2)T_(x),which is a novel two-dimensional(2 D)material,has received enormous interest in the field of sensor technology due to its large surface area,excellent electrical conductivity,and abundant active surfa...Ti_(3)C_(2)T_(x),which is a novel two-dimensional(2 D)material,has received enormous interest in the field of sensor technology due to its large surface area,excellent electrical conductivity,and abundant active surface sites.In recent years,several Ti_(3)C_(2)T_(x)-based gases and humidity sensors have been developed and reported.In this review,we focus on the latest applications of Ti_(3)C_(2)T_(x)-based nanomaterials in gas and humidity sensors.First,the synthesis of Ti_(3)C_(2)T_(x) from the dangerous fluorine-containing etching process to the safe fluorine-free preparation method was discussed,and the structures of the Ti_(3)C_(2)T_(x) controlled by different delamination methods were also outlined.Subsequently,the functionalization of pristine Ti_(3)C_(2)T_(x) and composite strategies for enhancing its gas and humidity sensing performance were reviewed.In addition,the gas and humidity sensing mechanisms of sensors based on Ti_(3)C_(2)T_(x) were also summarized.Finally,the challenges and opportunities for the use of Ti_(3)C_(2)T_(x) gas and humidity sensors were discussed to provide guidance on the promising potential of Ti_(3)C_(2)T_(x) in this field.展开更多
Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible ...Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible humidity sensors remains a challenge.In this work,a wearable capacitive-type Ga_(2)O_(3)/liquid metal-based humidity sensor is demonstrated by a one-step laser direct writing technique.Owing to the photothermal effect of laser,the Ga_(2)O_(3)-wrapped liquid metal particles can be selectively sintered and converted from insulative to conductive traces with a resistivity of 0.19Ω·cm,while the untreated regions serve as active sensing layers in response to moisture changes.Under 95%relative humidity,the humidity sensor displays a highly stable performance along with rapid response and recover time.Utilizing these superior properties,the Ga_(2)O_(3)/liquid metal-based humidity sensor is able to monitor human respiration rate,as well as skin moisture of the palm under different physiological states for healthcare monitoring.展开更多
This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type syste...This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%～70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.展开更多
Two-dimensional material has been widely investigated for potential applications in sensor and flexible electronics.In this work,a self-powered flexible humidity sensing device based on poly(vinyl alcohol)/Ti_(3)C_(2)...Two-dimensional material has been widely investigated for potential applications in sensor and flexible electronics.In this work,a self-powered flexible humidity sensing device based on poly(vinyl alcohol)/Ti_(3)C_(2)Tx(PVA/MXene)nanofibers film and monolayer molybdenum diselenide(MoSe2)piezoelectric nanogenerator(PENG)was reported for the first time.The monolayer MoSe_(2)-based PENG was fabricated by atmospheric pressure chemical vapor deposition techniques,which can generate a peak output of 35 mV and a power density of42 mW m^(-2).The flexible PENG integrated on polyethylene terephthalate(PET)substrate can harvest energy generated by different parts of human body and exhibit great application prospects in wearable devices.The electrospinned PVA/MXene nanofiber-based humidity sensor with flexible PET substrate under the driven of monolayer MoSe_(2) PENG,shows high response of~40,fast response/recovery time of 0.9/6.3 s,low hysteresis of 1.8%and excellent repeatability.The self-powered flexible humidity sensor yields the capability of detecting human skin moisture and ambient humidity.This work provides a pathway to explore the high-performance humidity sensor integrated with PENG for the self-powered flexible electronic devices.展开更多
In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interf...In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.展开更多
The effect of metal （Ti, Ni, and Au） electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer th...The effect of metal （Ti, Ni, and Au） electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer thermally grown on silicon substrate. The separation between the electrodes was 90 μm for all sensors. The sensors were tested from 40% to 90% relative humidity （RH） by AC electrical characterization at room temperature. When sensors are switched between 40% and 90% RH, the corresponding response and recovery time are 3 s and 5 s for Ti-electrode sensor, 4 s and 7 s for Ni-electrode sensor, and 7 s and 13 s for Au-electrode sensor. The hysteresis was 3%, 5% and 15% for sensitivity of Ti, Ni, and Au-electrode sensors are Ti-, Ni-, and Au-electrode sensor, respectively. The 7.53 MΩ/%RH, 5.29 MΩ/%RH and 4.01 MΩ/%RH respectively at 100 Hz. Therefore Ti-electrode sensor is found to have linear response, fast response and recovery time and higher sensitivity as compared with those of Ni- and Au-electrode sensors. Comparison of humidity sensing properties of sensors with different electrode material may propose a compelling route for designing and optimizing humidity sensors.展开更多
This study presents the fabrication and investigation （PANI） composite films. A blend of 3 wt.% OD with 1 of humidity sensors based on orange dye （OD） and polyaniline wt.% PANI was prepared in 1 ml water. The comp...This study presents the fabrication and investigation （PANI） composite films. A blend of 3 wt.% OD with 1 of humidity sensors based on orange dye （OD） and polyaniline wt.% PANI was prepared in 1 ml water. The composite films were deposited on glass substrates between pre-deposited silver electrodes. The gap between the electrodes was 45 um. The sensing mechanism was based on the impedance and capacitance variations due to the absorption/desorption of water vapor. It was observed that with the increase in relative humidity （RH） from 30% to 90%, the impedance decreases by 5.2 × 10^4 and 8.8 × 10^3 times for the frequencies of 120 Hz and 1 kHz, respectively. The impedance-humidity relationship showed a more uniform change compared to the capacitance-humidity relationship in the RH range of 30% to 90%. The consequence of annealing, measuring frequency, response and recovery time, and absorption-desorption behavior of the humidity sensor were also discussed in detail. The annealing resulted in an increase in sensitivity of up to 2.5 times, while the measured response time and recovery time were 34 s and 450 s, respectively. The impedance-humidity relationship was simulated.展开更多
A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis...A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis (< 4% RH) and quicker response (absorption: less than 2 s; desorption: less than 20 s) in comparison with sensor composed of NaPSS. The effect of concentration of NaPSS and TiO2 on humidity response of sensors was discussed.展开更多
This paper reported the impedance-type humidity sensor based on Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)nanomaterials which was fabricated on a flexible polyethylene terephthalate(PET)substrate.The scanning electron microscopy(S...This paper reported the impedance-type humidity sensor based on Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)nanomaterials which was fabricated on a flexible polyethylene terephthalate(PET)substrate.The scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)measurements were used to demonstrate the successful synthesis and combination of Ti_(3)C_(2)T_(x)and g-C_(3)N_(4)nanomaterials.The performance of the humidity sensor was tested at room temperature.The experimental results showed that the Ti_(3)C_(2)T_(x)nanosheets with g-C_(3)N_(4)nanosheets endowed the humidity sensor with an ultra-high response,rapid response/recovery time,and negligible hysteresis.The complex impedance spectroscopy(CIS)and bode diagrams were used to further analyze the sensing mechanism of the Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity sensor.The Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity sensor can monitor skin humidity and high-humidity alarm,which demonstrates great potential applications in various fields.展开更多
Robot＇s dynamic motion error and on-line compensation based on multi-axis force sensor are dealt with.It is revealed that the reasons of the error are formed and the relations of the error are delivered.A motion equa...Robot＇s dynamic motion error and on-line compensation based on multi-axis force sensor are dealt with.It is revealed that the reasons of the error are formed and the relations of the error are delivered.A motion equation of robot＇s termination with the error is established,and then,an error matrix and an error compensation matrix of the motion equation are also defined.An on-line error＇s compensation method is put forward to decrease the displacement error,which is a degree of millimeter,shown by the result of simulation of PUMA562 robot.展开更多
In this work,amido-graphene oxide(GO-NH_(2))loaded chitosan(CTS)composite material(CTS/GO-NH_(2))that acts as both the triboelectric and sensing film was prepared on rotary fan-shaped triboelectric nanogenerator for h...In this work,amido-graphene oxide(GO-NH_(2))loaded chitosan(CTS)composite material(CTS/GO-NH_(2))that acts as both the triboelectric and sensing film was prepared on rotary fan-shaped triboelectric nanogenerator for humidity detection.Compared with the pristine CTSbased triboelectric humidity sensor(CTS-THS)and GONH_(2)-THS,the CTS/GO-NH_(2)-based humidity sensor exhibited higher humidity response and better linearity in the relative humidity(RH)range of 18.7%RH-91.5%RH.The above results can be explained by the massive exposed and less concealed hydrophilic functional groups of CTS with the help of the wrinkle structure of GO-NH_(2).Meanwhile,the CTS/GO-NH_(2)-THS possessed good repeatability and acceptable hysteresis(~6.2%RH).Finally,a humidity sensing mechanism coupling triboelectric contact charging effect with electrons transfer principle under moisture environment was established to interpret the enhanced humidity sensing performance of the composite film-based THS.This work demonstrates that CTS/GONH_(2) composite film can be utilized to fabricate humidity sensors based on the triboelectric effect.展开更多
Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers show...Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers showing splendid sensing property is an urgent need in fields of materials and sensors,yet still at the initial stage.In this contribution,a new one-dimensional(1D)coordination polymer with formula of[Pb(TAA)(BA)(H_(2)O)]_(n)(namedasPbL,HTAA=3-thiopheneaceticacid,HBA=benzoic acid)has been successfully synthesized by a hydrothermal method,which involves in-situ synthesis of both decarboxylation and hydrolysis.As an impedimetric humidity sensing material,this coordination polymer exhibits excellent humidity sensing performance including high response,fast response,small hysteresis,and good repeatability.In the total relative humidity range(11%–97%)at room temperature,it is worth noting that the sensitivity of the humidity sensor is as high as 1.18×10^(4),the response time is only 2 s,and the max humidity hysteresis is as small as 1.8%.At last,we discussed the sensing mechanism using the alternating current(AC)impedance technique at various relative humidity.展开更多
As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this stu...As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this study,a facile chemical layer-by-layer self-assembly(CLS)method was developed for fabricating graphene oxide(GO)/polyethyleneimine(PEI)multilayer films.Owing to the chemical bonding between the PEI and GO,and the intrinsic stickiness of the PEI,layered films with different numbers of layers were successfully prepared using the CLS method and confirmed through ultraviolet-visible(UV-Vis)spectroscopy and the mass loading of quartz crystal microbalance(QCM).Morphological measurements revealed that the roughness and thickness of the films increased exponentially with the number of bilayers.The GO/PEI films were deposited on QCM electrodes using the CLS method to produce the humidity sensors.The humidity measurement results showed a high sensitivity(37.84 Hz/%RH)and rapid response/recovery(<5 s/8 s)of the optimal sensor,which was superior to that of recently developed QCM sensors.展开更多
The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the...The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the special working environnlent （e. g. cryogenic and vacuum） ,the measure error because of tile reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and tile fixing error of sensor and the error of machine tool＇s initial lignnlent are investigated. The mathematic model in every condition is founded, the simulation and relative experiments ale done and the outeome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is usefid to improvement of the signal-obtaining system.展开更多
Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative ...Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative humidity range of 10%～98%,indicating high humidity sensitivity of the sensors.At a certain measuring frequency,the capacitance of the sensors increases as increasing of the preparation pressure,while the sensitivity of the sensors basically remains the same.The frequencies corresponding to the peaks of the dielectric loss of the sensors move to the higher frequency direction as increasing of the relative humidity.At a certain humidity,the frequencies corresponding to the peaks of the dielectric loss move to the higher frequency direction as increasing of the preparation pressure.展开更多
The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and ...The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and character were studied in detail.The relationship between components of humidity resistance materials and negative temperature coefficient ( NTC) thermistor materials in sampling unit of compound sensor and character of electrical resistance and temperature was obtained.Couples of character curves of compound temperature-humidity sensor and data of materials of sampling unit were shown in this paper too.展开更多
ZnO films on R-sapphire substrates are prepared and characterized by x-ray diffraction and scanning electron microscopy, which indicate that the thin films are well crystallized with （1120） texture. Love wave and Ra...ZnO films on R-sapphire substrates are prepared and characterized by x-ray diffraction and scanning electron microscopy, which indicate that the thin films are well crystallized with （1120） texture. Love wave and Rayleigh wave are used for fabrications of humidity sensors, which are excited in [1100] and [0001] directions of the （1120） ZnO piezoelectric films, respectively. The experimental results show that both kinds of sensors have good humidity response and repeatability, and the performances of the Love wave sensors are better than those of the Rayleigh wave sensors at room temperature. Moreover, the theoretical calculations of the mass sensitivity of the sensors are a/so carried out and the calculated results are in good agreement with the experimental measurements.展开更多
基金supported by the Natural Science Project of Zhengzhou Science and Technology Bureau(No.21ZZXTCX12)the Key Research and Development Program of Henan Province(No.221111220300)+1 种基金the Key Program of the National Natural Science Foundation of China(No.62333013)the Youth Backbone Teacher Training Program of Henan University of Technology(No.21420154).
文摘To facilitate real-time monitoring and recording of humidity in the environment and to satisfy the requirement for strain performance in certain applications(such as wearable devices),this paper proposes an in-situ method for synthesising Au nanoparticles on ZIF-67.In this study,an Au@ZIF-67 composite humidity-sensitive material was combined with flexible polyethylene terephthalate interdigitated electrodes to create an Au@ZIF-67 flexible humidity sensor.The prepared samples were characterised using X-ray diffraction,X-ray photoelectron spectroscopy,and transmission electron microscopy.The humidity-sensitive properties of the sensor were investigated,and its monitoring capabilities in applications involving respiration,gestures,skin,and baby diapers were tested.The experimental results indicate that compared with a pure ZIF-67 humidity sensor,the Au@ZIF-67(0.1Au@Z)flexible humidity sensor exhibits a 158.07%decrease in baseline resistance and a 51.66%increase in sensitivity to 95%relative humidity,and the hysteresis,response time,and recovery time are significantly reduced.Furthermore,the sensor exhibits excellent characteristics such as high resolution,repeatability,and stability.The obtained results regarding the material properties,humidity sensitivity,and practical application of non-contact humidity monitoring demonstrate that the prepared sensors exhibit excellent and comprehensive performance,indicating their broad prospects in wearable medical devices,wireless Internet of Things,humidity detection in complex environments,and intelligent integrated systems.
文摘In order to solve the lack of relevant evaluation research on the accuracy of HMP155A humidity sensor calibration results in the past, this paper designs the corresponding experimental scheme, and obtains the corresponding calibration results according to the experimental scheme;Then the measurement uncertainty of the indication error in the calibration results is evaluated by GUM, and the corresponding extended uncertainty </span><i><span style="font-family:Verdana;">U</span></i><sub><span style="font-family:Verdana;">95</span></sub><span style="font-family:Verdana;"> is obtained. Finally, according to the requirements of JJF1094-2016 characteristic evaluation of measuring instruments, combined with the calibration results and the actual situation of </span><i><span style="font-family:Verdana;">U</span></i><sub><span style="font-family:Verdana;">95</span></sub><span style="font-family:Verdana;">, the conformity of the indication error of calibration is determined. The result is that each calibration point of the sensor meets the requirements of conformity determination and is within the qualified range. This research effectively makes up for the blank of the previous research on the conformity determination of the indication error of the calibration results and has strong theoretical and practical significance.
基金Jin Wu acknowledges financial support from the National Natural Science Foundation of China(No.61801525)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010693)+1 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22lgqb17)the Independent Fund of the State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-sen University)under grant No.OEMT-2022-ZRC-05.
文摘Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to avoid underlying risks,and for the early detection and treatment of diseases for home healthcare.Hydrogels with three-dimensional polymer networks and large amounts of water molecules are naturally flexible and stretchable.Functionalized hydrogels are intrinsically conductive,self-healing,self-adhesive,biocompatible,and room-temperature sensitive.Compared with traditional rigid vapor sensors,hydrogel-based gas and humidity sensors can directly fit human skin or clothing,and are more suitable for real-time monitoring of personal health and safety.In this review,current studies on hydrogel-based vapor sensors are investigated.The required properties and optimization methods of wearable hydrogel-based sensors are introduced.Subsequently,existing reports on the response mechanisms of hydrogel-based gas and humidity sensors are summarized.Related works on hydrogel-based vapor sensors for their application in personal health and safety monitoring are presented.Moreover,the potential of hydrogels in the field of vapor sensing is elucidated.Finally,the current research status,challenges,and future trends of hydrogel gas/humidity sensing are discussed.
基金financially supported by the National Natural Science Foundation of China(No.U19A2070)the National Science Funds for Excellent Young Scholars of China(No.61822106)the National Science Funds for Creative Research Groups of China(No.61421002)。
文摘Ti_(3)C_(2)T_(x),which is a novel two-dimensional(2 D)material,has received enormous interest in the field of sensor technology due to its large surface area,excellent electrical conductivity,and abundant active surface sites.In recent years,several Ti_(3)C_(2)T_(x)-based gases and humidity sensors have been developed and reported.In this review,we focus on the latest applications of Ti_(3)C_(2)T_(x)-based nanomaterials in gas and humidity sensors.First,the synthesis of Ti_(3)C_(2)T_(x) from the dangerous fluorine-containing etching process to the safe fluorine-free preparation method was discussed,and the structures of the Ti_(3)C_(2)T_(x) controlled by different delamination methods were also outlined.Subsequently,the functionalization of pristine Ti_(3)C_(2)T_(x) and composite strategies for enhancing its gas and humidity sensing performance were reviewed.In addition,the gas and humidity sensing mechanisms of sensors based on Ti_(3)C_(2)T_(x) were also summarized.Finally,the challenges and opportunities for the use of Ti_(3)C_(2)T_(x) gas and humidity sensors were discussed to provide guidance on the promising potential of Ti_(3)C_(2)T_(x) in this field.
基金This study was supported by the National Natural Science Foundation of China (52105593 and 62271439)STI 2030 —Major Projects(2022ZD0208601)the “Pioneer” and “Leading Goose” R&D Program of Zhejiang (2023C01051)。
文摘Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible humidity sensors remains a challenge.In this work,a wearable capacitive-type Ga_(2)O_(3)/liquid metal-based humidity sensor is demonstrated by a one-step laser direct writing technique.Owing to the photothermal effect of laser,the Ga_(2)O_(3)-wrapped liquid metal particles can be selectively sintered and converted from insulative to conductive traces with a resistivity of 0.19Ω·cm,while the untreated regions serve as active sensing layers in response to moisture changes.Under 95%relative humidity,the humidity sensor displays a highly stable performance along with rapid response and recover time.Utilizing these superior properties,the Ga_(2)O_(3)/liquid metal-based humidity sensor is able to monitor human respiration rate,as well as skin moisture of the palm under different physiological states for healthcare monitoring.
基金This work was supported by National Natural Science Foundation of China, Under Grant No.（60676044）
文摘This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%～70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.
基金supported by the National Natural Science Foundation of China(51777215)National Natural Science Foundation of China(51775306)+1 种基金Beijing Municipal Natural Science Foundation(4192027)the Graduate Innovation Fund of China University of Petroleum(YCX2020097)。
文摘Two-dimensional material has been widely investigated for potential applications in sensor and flexible electronics.In this work,a self-powered flexible humidity sensing device based on poly(vinyl alcohol)/Ti_(3)C_(2)Tx(PVA/MXene)nanofibers film and monolayer molybdenum diselenide(MoSe2)piezoelectric nanogenerator(PENG)was reported for the first time.The monolayer MoSe_(2)-based PENG was fabricated by atmospheric pressure chemical vapor deposition techniques,which can generate a peak output of 35 mV and a power density of42 mW m^(-2).The flexible PENG integrated on polyethylene terephthalate(PET)substrate can harvest energy generated by different parts of human body and exhibit great application prospects in wearable devices.The electrospinned PVA/MXene nanofiber-based humidity sensor with flexible PET substrate under the driven of monolayer MoSe_(2) PENG,shows high response of~40,fast response/recovery time of 0.9/6.3 s,low hysteresis of 1.8%and excellent repeatability.The self-powered flexible humidity sensor yields the capability of detecting human skin moisture and ambient humidity.This work provides a pathway to explore the high-performance humidity sensor integrated with PENG for the self-powered flexible electronic devices.
基金supported by the National Science and Technology Innovation 2030 Major Project(Grant No.2022ZD0208601)the National Natural Science Foundation of China(Grant No.52105593 and 51975513)the Natural Science Foundation of Zhejiang Province,China(No.LR20E050003)。
文摘In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.
基金support of the Higher Education Commission(HEC),Pakistan
文摘The effect of metal （Ti, Ni, and Au） electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer thermally grown on silicon substrate. The separation between the electrodes was 90 μm for all sensors. The sensors were tested from 40% to 90% relative humidity （RH） by AC electrical characterization at room temperature. When sensors are switched between 40% and 90% RH, the corresponding response and recovery time are 3 s and 5 s for Ti-electrode sensor, 4 s and 7 s for Ni-electrode sensor, and 7 s and 13 s for Au-electrode sensor. The hysteresis was 3%, 5% and 15% for sensitivity of Ti, Ni, and Au-electrode sensors are Ti-, Ni-, and Au-electrode sensor, respectively. The 7.53 MΩ/%RH, 5.29 MΩ/%RH and 4.01 MΩ/%RH respectively at 100 Hz. Therefore Ti-electrode sensor is found to have linear response, fast response and recovery time and higher sensitivity as compared with those of Ni- and Au-electrode sensors. Comparison of humidity sensing properties of sensors with different electrode material may propose a compelling route for designing and optimizing humidity sensors.
基金the Higher Education Commission of Pakistan for providing the financial support
文摘This study presents the fabrication and investigation （PANI） composite films. A blend of 3 wt.% OD with 1 of humidity sensors based on orange dye （OD） and polyaniline wt.% PANI was prepared in 1 ml water. The composite films were deposited on glass substrates between pre-deposited silver electrodes. The gap between the electrodes was 45 um. The sensing mechanism was based on the impedance and capacitance variations due to the absorption/desorption of water vapor. It was observed that with the increase in relative humidity （RH） from 30% to 90%, the impedance decreases by 5.2 × 10^4 and 8.8 × 10^3 times for the frequencies of 120 Hz and 1 kHz, respectively. The impedance-humidity relationship showed a more uniform change compared to the capacitance-humidity relationship in the RH range of 30% to 90%. The consequence of annealing, measuring frequency, response and recovery time, and absorption-desorption behavior of the humidity sensor were also discussed in detail. The annealing resulted in an increase in sensitivity of up to 2.5 times, while the measured response time and recovery time were 34 s and 450 s, respectively. The impedance-humidity relationship was simulated.
基金This work was supported by the National and Zhejiang Provincial Natural Science Foundation of China (No. 59773012).
文摘A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis (< 4% RH) and quicker response (absorption: less than 2 s; desorption: less than 20 s) in comparison with sensor composed of NaPSS. The effect of concentration of NaPSS and TiO2 on humidity response of sensors was discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.51777215 and 52005147)the Special Foundation of Taishan Scholar Project。
文摘This paper reported the impedance-type humidity sensor based on Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)nanomaterials which was fabricated on a flexible polyethylene terephthalate(PET)substrate.The scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)measurements were used to demonstrate the successful synthesis and combination of Ti_(3)C_(2)T_(x)and g-C_(3)N_(4)nanomaterials.The performance of the humidity sensor was tested at room temperature.The experimental results showed that the Ti_(3)C_(2)T_(x)nanosheets with g-C_(3)N_(4)nanosheets endowed the humidity sensor with an ultra-high response,rapid response/recovery time,and negligible hysteresis.The complex impedance spectroscopy(CIS)and bode diagrams were used to further analyze the sensing mechanism of the Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity sensor.The Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity sensor can monitor skin humidity and high-humidity alarm,which demonstrates great potential applications in various fields.
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program,No.2001AAA423300)Provincial Natural Science Foundation of Anhui,China(No.00043310)
文摘Robot＇s dynamic motion error and on-line compensation based on multi-axis force sensor are dealt with.It is revealed that the reasons of the error are formed and the relations of the error are delivered.A motion equation of robot＇s termination with the error is established,and then,an error matrix and an error compensation matrix of the motion equation are also defined.An on-line error＇s compensation method is put forward to decrease the displacement error,which is a degree of millimeter,shown by the result of simulation of PUMA562 robot.
基金financially supported by the Natural Science Foundation of China(No.U19A2070)the National Science Funds for Excellent Young Scholars of China(No.61822106)the National Science Funds for Creative Research Groups of China(No.61421002)。
文摘In this work,amido-graphene oxide(GO-NH_(2))loaded chitosan(CTS)composite material(CTS/GO-NH_(2))that acts as both the triboelectric and sensing film was prepared on rotary fan-shaped triboelectric nanogenerator for humidity detection.Compared with the pristine CTSbased triboelectric humidity sensor(CTS-THS)and GONH_(2)-THS,the CTS/GO-NH_(2)-based humidity sensor exhibited higher humidity response and better linearity in the relative humidity(RH)range of 18.7%RH-91.5%RH.The above results can be explained by the massive exposed and less concealed hydrophilic functional groups of CTS with the help of the wrinkle structure of GO-NH_(2).Meanwhile,the CTS/GO-NH_(2)-THS possessed good repeatability and acceptable hysteresis(~6.2%RH).Finally,a humidity sensing mechanism coupling triboelectric contact charging effect with electrons transfer principle under moisture environment was established to interpret the enhanced humidity sensing performance of the composite film-based THS.This work demonstrates that CTS/GONH_(2) composite film can be utilized to fabricate humidity sensors based on the triboelectric effect.
基金the National Natural Science Foundation of China(Nos.21601094,21401139 and 71804123)Tianjin Municipal Education Commission(No.2018KJ271)。
文摘Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers showing splendid sensing property is an urgent need in fields of materials and sensors,yet still at the initial stage.In this contribution,a new one-dimensional(1D)coordination polymer with formula of[Pb(TAA)(BA)(H_(2)O)]_(n)(namedasPbL,HTAA=3-thiopheneaceticacid,HBA=benzoic acid)has been successfully synthesized by a hydrothermal method,which involves in-situ synthesis of both decarboxylation and hydrolysis.As an impedimetric humidity sensing material,this coordination polymer exhibits excellent humidity sensing performance including high response,fast response,small hysteresis,and good repeatability.In the total relative humidity range(11%–97%)at room temperature,it is worth noting that the sensitivity of the humidity sensor is as high as 1.18×10^(4),the response time is only 2 s,and the max humidity hysteresis is as small as 1.8%.At last,we discussed the sensing mechanism using the alternating current(AC)impedance technique at various relative humidity.
基金financially supported by the National Natural Science Foundation of China(No.U19A2070)the National Science Funds for Excellent Young Scholars of China(No.61822106)the National Science Funds for Creative Research Groups of China(No.61421002)。
文摘As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this study,a facile chemical layer-by-layer self-assembly(CLS)method was developed for fabricating graphene oxide(GO)/polyethyleneimine(PEI)multilayer films.Owing to the chemical bonding between the PEI and GO,and the intrinsic stickiness of the PEI,layered films with different numbers of layers were successfully prepared using the CLS method and confirmed through ultraviolet-visible(UV-Vis)spectroscopy and the mass loading of quartz crystal microbalance(QCM).Morphological measurements revealed that the roughness and thickness of the films increased exponentially with the number of bilayers.The GO/PEI films were deposited on QCM electrodes using the CLS method to produce the humidity sensors.The humidity measurement results showed a high sensitivity(37.84 Hz/%RH)and rapid response/recovery(<5 s/8 s)of the optimal sensor,which was superior to that of recently developed QCM sensors.
文摘The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the special working environnlent （e. g. cryogenic and vacuum） ,the measure error because of tile reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and tile fixing error of sensor and the error of machine tool＇s initial lignnlent are investigated. The mathematic model in every condition is founded, the simulation and relative experiments ale done and the outeome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is usefid to improvement of the signal-obtaining system.
基金The project is supported by the National Natural Science Foundation of China （60074031, 60474052）.
文摘Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative humidity range of 10%～98%,indicating high humidity sensitivity of the sensors.At a certain measuring frequency,the capacitance of the sensors increases as increasing of the preparation pressure,while the sensitivity of the sensors basically remains the same.The frequencies corresponding to the peaks of the dielectric loss of the sensors move to the higher frequency direction as increasing of the relative humidity.At a certain humidity,the frequencies corresponding to the peaks of the dielectric loss move to the higher frequency direction as increasing of the preparation pressure.
文摘The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and character were studied in detail.The relationship between components of humidity resistance materials and negative temperature coefficient ( NTC) thermistor materials in sampling unit of compound sensor and character of electrical resistance and temperature was obtained.Couples of character curves of compound temperature-humidity sensor and data of materials of sampling unit were shown in this paper too.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174142,11304160 and 11404147the National Basic Research Program of China under Grant No 2012CB921504+2 种基金the PAPD Projectthe Natural Science Foundation of Jiangsu Higher Education Institutions of China under Grant No 13KJB140008the Foundation of Nanjing University of Posts and Telecommunications under Grant No NY213018
文摘ZnO films on R-sapphire substrates are prepared and characterized by x-ray diffraction and scanning electron microscopy, which indicate that the thin films are well crystallized with （1120） texture. Love wave and Rayleigh wave are used for fabrications of humidity sensors, which are excited in [1100] and [0001] directions of the （1120） ZnO piezoelectric films, respectively. The experimental results show that both kinds of sensors have good humidity response and repeatability, and the performances of the Love wave sensors are better than those of the Rayleigh wave sensors at room temperature. Moreover, the theoretical calculations of the mass sensitivity of the sensors are a/so carried out and the calculated results are in good agreement with the experimental measurements.
