Tin oxide （SnO2） is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphologicaJ ...Tin oxide （SnO2） is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphologicaJ and hydrogen gas sensing properties of SnO2 thin films synthesized by dc magnetron sputtering. The deposited samples are characterized by XRD, SEM, AFM, surface area measurements and surface profiler. Also the H2 gas sensing properties of SnO2 deposited samples are performed against a wide range of operating temperature. The XRD analysis demonstrates that the degree of crystallinity of the deposited SnO2 films strongly depends on the deposition time. SEM and AFM analyses reveal that the size of nanoparticles or agglomerates, and both average and rms surface roughness is enhanced with the increasing deposition time. Also gas sensors based on these SnO2 nanolayers show an acceptable response to hydrogen at various operating temperatures.展开更多
Owing to their high surface area,stable structure and easy fabrication,composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organi...Owing to their high surface area,stable structure and easy fabrication,composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds.Herein,a hydrothermal route is designed to prepare foam shapedα-MoO_(3)@SnS_(2)nanosheets that exhibit excellent sensing performance for triethylamine(TEA).The developed sensor,based onα-MoO_(3)@SnS_(2)nanosheets,displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175℃with sensitivity higher than many other reported sensors.In addition,the device shows a wide concentration detection range(from 500 ppb to 500 ppm),good stability after exposure to air for 80 days,and excellent selectivity.The superior sensing characteristics of the developed sensor are attributed to the high crystallinity ofα-MoO_(3)/SnS_(2),excessive and accessible active sites provided by the good permeability of porous SnS_(2)shells,and the excellent conductivity of the encapsulation heterojunction structure.Thus,the foam shapedα-MoO_(3)@SnS_(2)nanosheets presented herein have promising practical applications in TEA gas sensing devices.展开更多
Polyaniline （PANI） was prepared by the chemical oxidative polymerization of aniline, and ZnO, with the mean particle size of 28 nm, was synthesized by a non-aqueous solvent method. The organic-inorganic PANI/ZnO hyb...Polyaniline （PANI） was prepared by the chemical oxidative polymerization of aniline, and ZnO, with the mean particle size of 28 nm, was synthesized by a non-aqueous solvent method. The organic-inorganic PANI/ZnO hybrids with different mass fractions of PANI were obtained by mechanically mixing the prepared PANI and ZnO. The gas sensing properties of PANI/ZnO hybrids to different volatile organic compounds （VOCs） including methanol, ethanol and acetone were investigated at a low operating temperature of 90°C. Compared with the pure PANI and ZnO, the PANI/ZnO hybrids presented much higher response to VOCs. Meanwhile, the PANI/ZnO hybrid exhibited a good reversibility and a short response-recovery time, implying its potential application for gas sensors. The sensing mechanism was suggested to be related to the existence of p-n heterojunctions in the PANI/ZnO hybrids.展开更多
Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The...Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.展开更多
Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction...Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction interfaces.Among the various flexible sensor types,those with microstructure designs are considered promising for strain sensing due to their simple structure,high sensitivity,extensive operational range,rapid response time,and robust stability.This review provides a concise overview of recent advancements in flexible piezoresistive sensors based on microstructure design for enhanced strain sensing performance,including the impact of microstructure on sensing mechanisms,classification of microstructure designs,fabrication methods,and practical applications.Initially,this review delves into the analysis of piezoresistive sensor sensing mechanisms and performance parameters,exploring the relationship between microstructure design and performance enhancement.Subsequently,an in-depth discussion is presented,focusing on the primary themes of microstructure design classification,process selection,performance characteristics,and specific applications.This review employs mathematical modeling and hierarchical analysis to emphasize the directionality of different microstructures on performance enhancement and to highlight the performance advantages and applicable features of various microstructure types.In conclusion,this review examines the multifunctionality of flexible piezoresistive sensors based on microstructure design and addresses the challenges that still need to be overcome and improved,such as achieving a wide range of stretchability,high sensitivity,and robust stability.This review summarizes the research directions for enhancing sensing performance through microstructure design,aiming to assist in the advancement of flexible piezoresistive sensors.展开更多
Controllably tuning the sensing performance of flexible mechanical sensors is important for them to realize on-demand sensing of various mechanical stimuli in different application scenarios.However,current regulating...Controllably tuning the sensing performance of flexible mechanical sensors is important for them to realize on-demand sensing of various mechanical stimuli in different application scenarios.However,current regulating strategies focus on the construction process of individual sensors,the response performance of the as-formed sensors is still hard to autonomously tune with external stimulus changes like human skin.Here,we propose a new strategy that realizes post-tuning of the sensing performance by introducing a temperature-dependent phase transition elastomer into the sensing film.Through an interfacially confined photopolymerization reaction,a graphene-based phase-transition elastomeric(GPTE)film with a robust interface and excellent conductivity is well-formed at the water/air interface.Benefiting from the crystallization-melt dynamic switching in the elastomer network,the GPTE film could experience the reversible transformation between soft(1.65 MPa)and stiff(12.27MPa)states,showing huge changes of elastic modulus up to seven times near the phase transition temperature(28.5℃).Furthermore,the GPTE film is designed into a suspended perceptual configuration realizing the dynamic detection of 3D deformation adapted to temperature changes with up to 3.5-fold difference in response sensitivity.Finally,the self-adaptive sensing behavior of temperature-mediated 3D deformation is demonstrated by the effective detection of the dynamic stimulation process of cold and hot water droplets by the GPTE suspended film.The proposed strategy of phase transition-induced post-tuning of sensing performance could greatly facilitate flexible mechanical sensors towards a more intelligent one.展开更多
Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The prin...Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio(SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 d B higher than that with single wavelength, the Brillouin frequency shift(BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed technique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.展开更多
Figure 6(a)in the paper[Chin.Phys.B 33074203(2024)]was incorrect due to editorial oversight.The correct figure is provided.This modification does not affect the result presented in the paper.
Fiber specklegram sensors are widely studied for their high sensitivity and compact design.However,as the number of modes in the fiber increased,the speckle sensitivity heightened along with the correlation diminished...Fiber specklegram sensors are widely studied for their high sensitivity and compact design.However,as the number of modes in the fiber increased,the speckle sensitivity heightened along with the correlation diminished,lowering the sensing performance.In this paper,an innovative method is introduced based on digital aperture filtering(DAF)that adopts physical principle analysis,which reduces the collection aperture by computationally screening out the energy of higher-order modes within the speckle,therefore enhancing the correlation among speckles.Subsequently,a multi-layer convolutional neural network is designed to accurately and efficiently identify the measurands represented from the filtered speckles.By comparing the experimental results of the speckle demodulation method on different multimode fibers in light field direction sensing,the DAF method has shown outstanding performance in sensing accuracy,sensing range,stability,resolution,and generalizability,fully demonstrating its tremendous potential in the advancement of fiber sensing technology.展开更多
As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,...As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,the internet of things,and other fields.In recent years,highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms.Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance.This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors.We discuss different architectures and morphological designs of sensing materials to achieve high performance,including high sensitivity,broad working range,stable sensing,low hysteresis,high transparency,and directional or selective sensing.Additionally,the general fabrication techniques are summarized,including self-assembly,patterning,and auxiliary synthesis methods.Furthermore,we present the emerging applications of high-performing microengineered pressure sensors in healthcare,smart homes,digital sports,security monitoring,and machine learning-enabled computational sensing platform.Finally,the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.展开更多
Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propo...Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.展开更多
Wearable and stretchable strain sensors have potential values in the fields of human motion and health monitoring,flexible electronics,and soft robotic skin.The wearable and stretchable strain sensors can be directly ...Wearable and stretchable strain sensors have potential values in the fields of human motion and health monitoring,flexible electronics,and soft robotic skin.The wearable and stretchable strain sensors can be directly attached to human skin,providing visualized detection for human motions and personal healthcare.Conductive polymer composites(CPC)composed of conductive fillers and flexible polymers have the advantages of high stretchability,good flexibility,superior durability,which can be used to prepare flexible strain sensors with large working strain and outstanding sensitivity.This review has put forward a comprehensive summary on the fabrication methods,advanced mechanisms and strain sensing abilities of CPC strain sensors reported in recent years,especially the sensors with superior performance.Finally,the structural design,bionic function,integration technology and further application of CPC strain sensors are prospected.展开更多
Flexible strain sensors have garnered significant attention for their potential applications in advanced flexible electronics and wearable technologies.However,achieving stable signal transmission at high temperatures...Flexible strain sensors have garnered significant attention for their potential applications in advanced flexible electronics and wearable technologies.However,achieving stable signal transmission at high temperatures remains a major challenge.In this study,we developed a novel polyimide(PI)aerogel composite,reinforced with intrinsically short-cut polyimide nanofibers(PINF)that are surface-coated with silver nanoparticles to enhance both conductivity and mechanical strength.Carbon nanotubes(CNTs)are used as the main filler in synergistic effect with Ag@PINF particles to further improve the conductivity and sensing performance of the composite material.This synergistic design results in a flexible PI aerogel composite material with rapid response time(116 ms),high sensitivity(GF=3.12),and long-term cycling stability(>1000 cycles).Additionally,the sensing materials were tested at high temperatures and after high-temperature aging,demonstrating good flexible sensing performance.Experimental results demonstrate that the composite sensor maintains stable strain-sensing performance across a range of environmental temperatures,showing consistent strain response under the same deformation conditions.This work provides a promising approach for fabricating high-performance,temperature-resistant flexible strain sensors,with broad applications in flexible electronics and wearable technologies.展开更多
With the rapid development of flexible wearable electronic devices,a multifunctional electronic skin with excellent strain sensing performance,satisfactory air permeability,and good self-powered capability for portabi...With the rapid development of flexible wearable electronic devices,a multifunctional electronic skin with excellent strain sensing performance,satisfactory air permeability,and good self-powered capability for portability is urgently desired.Herein,inspired by the“brick-and-mortar”microstructure of natural nacre,an ultra-stretchable and highly sensitive multifunctional e-skin composed of Ti_(3)C_(2)T_(x)(MXene)/Carbon nanotubes(CNTs)/thermoplastic polyurethane films is developed through electrospinning and spraying technology.Benefiting from the tunable multilayer structural design,the multifunctional e-skin synchronously demonstrates a high sensitivity(gauge factor,GF_(max)=5.8×10^(4)),wide sensing range(up to 535%strain),low detection limit(0.15%strain),fast response time(80 ms)and good durability.The sensing mechanism is developed based on the evolution of a two-dimensional(2D)MXene/1D CNTs synergistic conductive network and the expansion of the microcracked structure synchronously.The multifunctional e-skin is also assembled as a single-electrode triboelectric nanogenerator,which shows high triboelectric output and good stability,broadening the application of the multifunctional e-skin in tactile sensing.The nacre-mimetic self-powered e-skin is demonstrated for human physiological signal acquisition,cardiopulmonary resuscitation(CPR),and posture correction training,presenting fascinating application strategies for ergonomics,emergency medical services,and athlete training assessment.展开更多
Based on optofluidics and whispering gallery mode(WGM)theory,here an optofluidic refractive index sensor with microtube-coupled suspended core fiber(SCF)is proposed.It solves the issues of general sensors with microca...Based on optofluidics and whispering gallery mode(WGM)theory,here an optofluidic refractive index sensor with microtube-coupled suspended core fiber(SCF)is proposed.It solves the issues of general sensors with microcavity-coupled fiber taper such as too fragile,unstable performance due to open coupling,poor portability and repeatability,while overcoming the poor performance of low refractive index sensing in general full-package fiber sensors.The sensor only needs a very small amount of liquid sample(about 1.8 nL).The proposed sensor combines the excellent performance of full package,optofluidics and WGM resonator.The resonant characteristics and sensing performance of the sensor are analyzed and discussed by the theoretical simulation.The simulation results indicate that the sensor has a wide refractive index sensing range(1.330-1.700)and good performance.The resonance wavelength shift has a good linear relationship with the liquid refractive index variation.In the low refractive index region,the sensitivity is 222.5-247.5 nm/RIU,Q-factor is 1.03×10^(3) and the detection limit is 3.64×10^(-4) RIU.In the medium and high refractive index regions,the sensitivity is 564.4-846.2 nm/RIU,Q-factor is up to 8.62×10^(4),and the detection limit can be as low as 1.29×10^(-6) RIU.The sensor exhibits a high sensitivity,a high Q-factor and a very low detection limit.展开更多
The need for high-performance and cost-effective gas sensors in industrial and domestic settings has led to ad-vancements in gas sensors based on metal-organic frameworks(MOFs).However,challenges remain in the design ...The need for high-performance and cost-effective gas sensors in industrial and domestic settings has led to ad-vancements in gas sensors based on metal-organic frameworks(MOFs).However,challenges remain in the design and synthesis of MOFs with customized structure and affinity toward targeted gases and their integration onto miniaturized electronic devices.The deliberate design of MOFs with desired characteristics is hindered by limited understanding of the interactions between MOFs and analytes.Furthermore,there is a lack of customization of relevant MOF-based sensors with salient sensing performance and their integration into sensor arrays to align with different application scenarios.The combination of machine learning or artificial intelligence(AI)with gas sensors also represents a promising avenue for future research.Herein,we provide a mini-review of recent ac-complishments in MOF-based gas sensors,covering materials design and device integration.The challenges of miniaturization and building smart sensing systems with anomaly detection,self-calibration,and lifetime pre-diction are also discussed.展开更多
An acidic gas is an important basic chemical raw material used for synthesizing fertilizers,insecticides,explosives,dyes,and salts.Alternatively,inorganic acidic gases that leak into the air have harmful effects on th...An acidic gas is an important basic chemical raw material used for synthesizing fertilizers,insecticides,explosives,dyes,and salts.Alternatively,inorganic acidic gases that leak into the air have harmful effects on the human health,infrastructure,and cultural relics.Therefore,the demand for inorganic acidic gas sensors for air quality monitoring and management has continuously increased,enabling the development of various sensing technologies.Among them,fiber-optic sensors are promising for acidic gas detection because of their excellent in-situ measurement,resistance to corrosion,anti-electromagnetic interference,long service life,and smart structure.In particular,fiber-optic sensors have proven to be very useful for the in-situ detection and distributed monitoring of multiple gas parameters.However,the sensitivity,selectivity,repeatability,and limits of detection of these sensors can be improved to achieve acceptable performance levels for practical applications.In this review,we introduce fiber-optic sensors based on structured optical fibers and fiber gratings for detecting H_(2)S,SO_(2),NO_(2),CO_(2),and N_(2)O.The structures of the sensing regions,gas-sensitive materials,and measurement principles of these sensors are presented.The sensitivity,selectivity,limit of detection,and response time of the sensors are summarized.Finally,the future of fiber-optic sensors for the detection of inorganic acidic gases is discussed.展开更多
Wearable gas sensors can improve early warning provision for workers in special worksites and can also be used as flexible electronic platforms.Here,the flexible multifunctional gas sensor was prepared by grafting gra...Wearable gas sensors can improve early warning provision for workers in special worksites and can also be used as flexible electronic platforms.Here,the flexible multifunctional gas sensor was prepared by grafting graphene oxide(GO)-Ag onto cotton fabric after swelling.The maximum bacterial inhibition rate of GO-150/cotton fabric was 95.6%for E.coli and 87.6%for S.aureus,while retaining the original high moisture permeability of cotton fabric.So GO/cotton fabric can resist the multiplication of bacteria.At the same time,GO can greatly improve the UV protection performance of cotton fabric used in garments.With increase of the GO concentration,the UV protection ability of composite fabric is enhanced.Finally,GO-Ag/cotton fabric sensors had stable NH3 gassensitive properties and good washing stability.In conclusion,these cotton fabric sensors with antibacterial properties,UV resistance and highly sensitive gas-sensitive properties have potential applications in wearable early warning devices and textile products.展开更多
Integration and synergy of the unique functions of different components have been developed into one of the most convenient and effective ways to construct the composite advanced materials with collective properties a...Integration and synergy of the unique functions of different components have been developed into one of the most convenient and effective ways to construct the composite advanced materials with collective properties and improved performances.In this work,the mace-like tetrathiafulvalene-tetracyanoquinodimethane(TTF-TCNQ)/HKUST-1 composite structures with single single-crystalline TTF-TCNQ submicrorods covered by ordered HKUST-1 nanosheet arrays were successfully constructed by an efficient TTF-TCNQ seed-mediated growth approach.Impressively,thanks to the synergetic and complementary effects between TTF-TCNQ and HKUST-1,the sensors based on such mace-like TTF-TCNQ/HKUST-1 composite structures not only displayed an experimental detection limit of 10 part per billion(ppb)for NO_(2) detection,but also exhibited outstanding selectivity even if the concentration of the interfering gases was 10 times that of NO_(2).Meanwhile,good reproducibility and rapid response were also achieved.This work opens the avenue for creation of novel high-performance sensing materials for application in gas sensing.展开更多
基金Supported by the Bandar Abbas Branch of the Islamic Azad University
文摘Tin oxide （SnO2） is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphologicaJ and hydrogen gas sensing properties of SnO2 thin films synthesized by dc magnetron sputtering. The deposited samples are characterized by XRD, SEM, AFM, surface area measurements and surface profiler. Also the H2 gas sensing properties of SnO2 deposited samples are performed against a wide range of operating temperature. The XRD analysis demonstrates that the degree of crystallinity of the deposited SnO2 films strongly depends on the deposition time. SEM and AFM analyses reveal that the size of nanoparticles or agglomerates, and both average and rms surface roughness is enhanced with the increasing deposition time. Also gas sensors based on these SnO2 nanolayers show an acceptable response to hydrogen at various operating temperatures.
基金financially supported by the National Natural Science Foundation of China(No.51227804)funded by the Postdoctoral Scientific Research Foundation of Qingdao,National College Students Innovation and Entrepreneurship Training Program of China(No.G201911065028)+3 种基金College Students Innovation and Entrepreneurship Training Program of Qingdao University(Nos.X201911065058,X202011065056)Natural Science Foundation of Shandong Province(No.ZR2019YQ24)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)。
文摘Owing to their high surface area,stable structure and easy fabrication,composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds.Herein,a hydrothermal route is designed to prepare foam shapedα-MoO_(3)@SnS_(2)nanosheets that exhibit excellent sensing performance for triethylamine(TEA).The developed sensor,based onα-MoO_(3)@SnS_(2)nanosheets,displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175℃with sensitivity higher than many other reported sensors.In addition,the device shows a wide concentration detection range(from 500 ppb to 500 ppm),good stability after exposure to air for 80 days,and excellent selectivity.The superior sensing characteristics of the developed sensor are attributed to the high crystallinity ofα-MoO_(3)/SnS_(2),excessive and accessible active sites provided by the good permeability of porous SnS_(2)shells,and the excellent conductivity of the encapsulation heterojunction structure.Thus,the foam shapedα-MoO_(3)@SnS_(2)nanosheets presented herein have promising practical applications in TEA gas sensing devices.
基金financially supported by the National Natural Science Foundation of China(No.21171099)Science and Technology Commission Foundation of Tianjin(Nos.09JCYBJC03600 and 10JCYBJC03900)
文摘Polyaniline （PANI） was prepared by the chemical oxidative polymerization of aniline, and ZnO, with the mean particle size of 28 nm, was synthesized by a non-aqueous solvent method. The organic-inorganic PANI/ZnO hybrids with different mass fractions of PANI were obtained by mechanically mixing the prepared PANI and ZnO. The gas sensing properties of PANI/ZnO hybrids to different volatile organic compounds （VOCs） including methanol, ethanol and acetone were investigated at a low operating temperature of 90°C. Compared with the pure PANI and ZnO, the PANI/ZnO hybrids presented much higher response to VOCs. Meanwhile, the PANI/ZnO hybrid exhibited a good reversibility and a short response-recovery time, implying its potential application for gas sensors. The sensing mechanism was suggested to be related to the existence of p-n heterojunctions in the PANI/ZnO hybrids.
基金supported by the National Natural Science Foundation of China (No. 20871071)the Science and Technology Commission Foundation of Tianjin (Nos. 09JCYBJC03600 and 10JCYBJC03900)
文摘Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.
基金supported by the National Natural Science Foundation of China(No.52204299)the Natural Science Foundation of Hunan Province(Nos.2022JJ40623 and 2022JJ30722)the Start-Up Funds for Outstanding Talents in Central South University(Nos.202045007 and 202044017).
文摘Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction interfaces.Among the various flexible sensor types,those with microstructure designs are considered promising for strain sensing due to their simple structure,high sensitivity,extensive operational range,rapid response time,and robust stability.This review provides a concise overview of recent advancements in flexible piezoresistive sensors based on microstructure design for enhanced strain sensing performance,including the impact of microstructure on sensing mechanisms,classification of microstructure designs,fabrication methods,and practical applications.Initially,this review delves into the analysis of piezoresistive sensor sensing mechanisms and performance parameters,exploring the relationship between microstructure design and performance enhancement.Subsequently,an in-depth discussion is presented,focusing on the primary themes of microstructure design classification,process selection,performance characteristics,and specific applications.This review employs mathematical modeling and hierarchical analysis to emphasize the directionality of different microstructures on performance enhancement and to highlight the performance advantages and applicable features of various microstructure types.In conclusion,this review examines the multifunctionality of flexible piezoresistive sensors based on microstructure design and addresses the challenges that still need to be overcome and improved,such as achieving a wide range of stretchability,high sensitivity,and robust stability.This review summarizes the research directions for enhancing sensing performance through microstructure design,aiming to assist in the advancement of flexible piezoresistive sensors.
基金supported by the National Key Research and Development Program of China(No.2022YFC2805200)the National Natural Science Foundation of China(No.52373094)+4 种基金Zhejiang Provincial Natural Science Foundation(No.LR25E030004)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2023313)Sino-German Mobility Program(No.M-0424),Ningbo Major Research and Development Plan Project(No.20241ZDYF020148)Ningbo International Cooperation(No.2023H019)Ningbo Science&Technology Bureau(No.2024QL003)。
文摘Controllably tuning the sensing performance of flexible mechanical sensors is important for them to realize on-demand sensing of various mechanical stimuli in different application scenarios.However,current regulating strategies focus on the construction process of individual sensors,the response performance of the as-formed sensors is still hard to autonomously tune with external stimulus changes like human skin.Here,we propose a new strategy that realizes post-tuning of the sensing performance by introducing a temperature-dependent phase transition elastomer into the sensing film.Through an interfacially confined photopolymerization reaction,a graphene-based phase-transition elastomeric(GPTE)film with a robust interface and excellent conductivity is well-formed at the water/air interface.Benefiting from the crystallization-melt dynamic switching in the elastomer network,the GPTE film could experience the reversible transformation between soft(1.65 MPa)and stiff(12.27MPa)states,showing huge changes of elastic modulus up to seven times near the phase transition temperature(28.5℃).Furthermore,the GPTE film is designed into a suspended perceptual configuration realizing the dynamic detection of 3D deformation adapted to temperature changes with up to 3.5-fold difference in response sensitivity.Finally,the self-adaptive sensing behavior of temperature-mediated 3D deformation is demonstrated by the effective detection of the dynamic stimulation process of cold and hot water droplets by the GPTE suspended film.The proposed strategy of phase transition-induced post-tuning of sensing performance could greatly facilitate flexible mechanical sensors towards a more intelligent one.
基金supported by the National Natural Science Foundation of China(No.61377088)the Natural Science Foundation of Hebei Province of China(Nos.E2015502053 and F2015502059)the Fundamental Research Funds for the Central Universities(No.2016XS104)
文摘Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio(SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 d B higher than that with single wavelength, the Brillouin frequency shift(BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed technique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.
文摘Figure 6(a)in the paper[Chin.Phys.B 33074203(2024)]was incorrect due to editorial oversight.The correct figure is provided.This modification does not affect the result presented in the paper.
基金supported by the National Natural Science Foundation of China(No.52375549)the Nankai University Eye Institute(Nos.NKYKD202204 and NKYKK202209)+2 种基金the China Postdoctoral Science Foundation(No.2022M721695)the Enterprise R&D Special Project of Tiankai Higher Education Science and Technology Innovation Park(No.23YFZXYC00041)the Fundamental Research Funds for the Central Universities,Nankai University(No.63241331)。
文摘Fiber specklegram sensors are widely studied for their high sensitivity and compact design.However,as the number of modes in the fiber increased,the speckle sensitivity heightened along with the correlation diminished,lowering the sensing performance.In this paper,an innovative method is introduced based on digital aperture filtering(DAF)that adopts physical principle analysis,which reduces the collection aperture by computationally screening out the energy of higher-order modes within the speckle,therefore enhancing the correlation among speckles.Subsequently,a multi-layer convolutional neural network is designed to accurately and efficiently identify the measurands represented from the filtered speckles.By comparing the experimental results of the speckle demodulation method on different multimode fibers in light field direction sensing,the DAF method has shown outstanding performance in sensing accuracy,sensing range,stability,resolution,and generalizability,fully demonstrating its tremendous potential in the advancement of fiber sensing technology.
基金supported by the National Natural Science Foundation of China(52003253 and 52103308)the China Postdoctoral Science Foundation(2020M672283).
文摘As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,the internet of things,and other fields.In recent years,highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms.Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance.This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors.We discuss different architectures and morphological designs of sensing materials to achieve high performance,including high sensitivity,broad working range,stable sensing,low hysteresis,high transparency,and directional or selective sensing.Additionally,the general fabrication techniques are summarized,including self-assembly,patterning,and auxiliary synthesis methods.Furthermore,we present the emerging applications of high-performing microengineered pressure sensors in healthcare,smart homes,digital sports,security monitoring,and machine learning-enabled computational sensing platform.Finally,the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.
基金Project supported by the National Natural Science Foundation of China(Grant No.NSFC 12175107)the Natural Science Foundation of Nanjing Vocational University of Industry Technology,China(Grant No.YK22-02-08)+3 种基金the Qing Lan Project of Jiangsu Province,Chinathe Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX23_0964)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20230347)the Fund from the Research Center of Industrial Perception and Intelligent Manufacturing Equipment Engineering of Jiangsu Province,China(Grant No.ZK21-05-09)。
文摘Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2021R1A2C1008380)Nano Material Technology Development Program[NRF-2015M3A7B6027970]+1 种基金the Chey Institute for Advanced Studies'International Scholar Exchange Fellowship for the academic year of 2021-2022supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government(MOTIE)(20215710100170).
文摘Wearable and stretchable strain sensors have potential values in the fields of human motion and health monitoring,flexible electronics,and soft robotic skin.The wearable and stretchable strain sensors can be directly attached to human skin,providing visualized detection for human motions and personal healthcare.Conductive polymer composites(CPC)composed of conductive fillers and flexible polymers have the advantages of high stretchability,good flexibility,superior durability,which can be used to prepare flexible strain sensors with large working strain and outstanding sensitivity.This review has put forward a comprehensive summary on the fabrication methods,advanced mechanisms and strain sensing abilities of CPC strain sensors reported in recent years,especially the sensors with superior performance.Finally,the structural design,bionic function,integration technology and further application of CPC strain sensors are prospected.
基金Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(No.JCKYS2024603C009).
文摘Flexible strain sensors have garnered significant attention for their potential applications in advanced flexible electronics and wearable technologies.However,achieving stable signal transmission at high temperatures remains a major challenge.In this study,we developed a novel polyimide(PI)aerogel composite,reinforced with intrinsically short-cut polyimide nanofibers(PINF)that are surface-coated with silver nanoparticles to enhance both conductivity and mechanical strength.Carbon nanotubes(CNTs)are used as the main filler in synergistic effect with Ag@PINF particles to further improve the conductivity and sensing performance of the composite material.This synergistic design results in a flexible PI aerogel composite material with rapid response time(116 ms),high sensitivity(GF=3.12),and long-term cycling stability(>1000 cycles).Additionally,the sensing materials were tested at high temperatures and after high-temperature aging,demonstrating good flexible sensing performance.Experimental results demonstrate that the composite sensor maintains stable strain-sensing performance across a range of environmental temperatures,showing consistent strain response under the same deformation conditions.This work provides a promising approach for fabricating high-performance,temperature-resistant flexible strain sensors,with broad applications in flexible electronics and wearable technologies.
基金supported by the National Natural Science Foundation of China(52303114,52173048)China Postdoctoral Science Foundation(2023M733199,2024T170838)。
文摘With the rapid development of flexible wearable electronic devices,a multifunctional electronic skin with excellent strain sensing performance,satisfactory air permeability,and good self-powered capability for portability is urgently desired.Herein,inspired by the“brick-and-mortar”microstructure of natural nacre,an ultra-stretchable and highly sensitive multifunctional e-skin composed of Ti_(3)C_(2)T_(x)(MXene)/Carbon nanotubes(CNTs)/thermoplastic polyurethane films is developed through electrospinning and spraying technology.Benefiting from the tunable multilayer structural design,the multifunctional e-skin synchronously demonstrates a high sensitivity(gauge factor,GF_(max)=5.8×10^(4)),wide sensing range(up to 535%strain),low detection limit(0.15%strain),fast response time(80 ms)and good durability.The sensing mechanism is developed based on the evolution of a two-dimensional(2D)MXene/1D CNTs synergistic conductive network and the expansion of the microcracked structure synchronously.The multifunctional e-skin is also assembled as a single-electrode triboelectric nanogenerator,which shows high triboelectric output and good stability,broadening the application of the multifunctional e-skin in tactile sensing.The nacre-mimetic self-powered e-skin is demonstrated for human physiological signal acquisition,cardiopulmonary resuscitation(CPR),and posture correction training,presenting fascinating application strategies for ergonomics,emergency medical services,and athlete training assessment.
基金supported by the National Natural Science Foundation of China(No.12174199)the Wanjing Horizontal Research and Development Fund for Nature(No.HJ1060319960015).
文摘Based on optofluidics and whispering gallery mode(WGM)theory,here an optofluidic refractive index sensor with microtube-coupled suspended core fiber(SCF)is proposed.It solves the issues of general sensors with microcavity-coupled fiber taper such as too fragile,unstable performance due to open coupling,poor portability and repeatability,while overcoming the poor performance of low refractive index sensing in general full-package fiber sensors.The sensor only needs a very small amount of liquid sample(about 1.8 nL).The proposed sensor combines the excellent performance of full package,optofluidics and WGM resonator.The resonant characteristics and sensing performance of the sensor are analyzed and discussed by the theoretical simulation.The simulation results indicate that the sensor has a wide refractive index sensing range(1.330-1.700)and good performance.The resonance wavelength shift has a good linear relationship with the liquid refractive index variation.In the low refractive index region,the sensitivity is 222.5-247.5 nm/RIU,Q-factor is 1.03×10^(3) and the detection limit is 3.64×10^(-4) RIU.In the medium and high refractive index regions,the sensitivity is 564.4-846.2 nm/RIU,Q-factor is up to 8.62×10^(4),and the detection limit can be as low as 1.29×10^(-6) RIU.The sensor exhibits a high sensitivity,a high Q-factor and a very low detection limit.
基金supported by the National Natural Science Foundation of China(22201226)the Natural Science Foundation of Shannxi(2022JQ-469)+2 种基金the Special Fund for Basic Scientific Research of Central College of Chang an University(No.300102313110)support from"High-Level Overseas Talent Returming to China"projectthe support from Xi'an Jiaotong University within the framework of the"Young Talent Support Plan".
文摘The need for high-performance and cost-effective gas sensors in industrial and domestic settings has led to ad-vancements in gas sensors based on metal-organic frameworks(MOFs).However,challenges remain in the design and synthesis of MOFs with customized structure and affinity toward targeted gases and their integration onto miniaturized electronic devices.The deliberate design of MOFs with desired characteristics is hindered by limited understanding of the interactions between MOFs and analytes.Furthermore,there is a lack of customization of relevant MOF-based sensors with salient sensing performance and their integration into sensor arrays to align with different application scenarios.The combination of machine learning or artificial intelligence(AI)with gas sensors also represents a promising avenue for future research.Herein,we provide a mini-review of recent ac-complishments in MOF-based gas sensors,covering materials design and device integration.The challenges of miniaturization and building smart sensing systems with anomaly detection,self-calibration,and lifetime pre-diction are also discussed.
基金the National Natural Science Foundation of China(Grant Nos.52176178 and 52304321)Chongqing Natural Science Foundation Innovation and Development Joint Fund(Municipal Education Commission)Project(Grant No.CSTB2022NSCQLZX0059)+5 种基金Major Scientific and Technological Research Project of Chongqing Municipal Education Commission(Grant No.KJZD-M202201101)Key Research&Development Projects of Sichuan Provincial Science and Technology Plan(Grant No.2023YFS0455)Meishan Science and Technology Plan Project(Grant No.2022ZYZF13)Chongqing Talent Project(Grant No.cstc2022ycjh-bgzxm0241)Innovation Research Group of Universities in Chongqing(Grant No.CXQT21035)Chongqing Postgraduate Innovation Project(Grant No.CYS23661).
文摘An acidic gas is an important basic chemical raw material used for synthesizing fertilizers,insecticides,explosives,dyes,and salts.Alternatively,inorganic acidic gases that leak into the air have harmful effects on the human health,infrastructure,and cultural relics.Therefore,the demand for inorganic acidic gas sensors for air quality monitoring and management has continuously increased,enabling the development of various sensing technologies.Among them,fiber-optic sensors are promising for acidic gas detection because of their excellent in-situ measurement,resistance to corrosion,anti-electromagnetic interference,long service life,and smart structure.In particular,fiber-optic sensors have proven to be very useful for the in-situ detection and distributed monitoring of multiple gas parameters.However,the sensitivity,selectivity,repeatability,and limits of detection of these sensors can be improved to achieve acceptable performance levels for practical applications.In this review,we introduce fiber-optic sensors based on structured optical fibers and fiber gratings for detecting H_(2)S,SO_(2),NO_(2),CO_(2),and N_(2)O.The structures of the sensing regions,gas-sensitive materials,and measurement principles of these sensors are presented.The sensitivity,selectivity,limit of detection,and response time of the sensors are summarized.Finally,the future of fiber-optic sensors for the detection of inorganic acidic gases is discussed.
基金We thank the Scientific Research Foundation of Zhejiang Sci-Tech University(ZSTU)under Grant Nos.19082472-Y and 19012099-Y.
文摘Wearable gas sensors can improve early warning provision for workers in special worksites and can also be used as flexible electronic platforms.Here,the flexible multifunctional gas sensor was prepared by grafting graphene oxide(GO)-Ag onto cotton fabric after swelling.The maximum bacterial inhibition rate of GO-150/cotton fabric was 95.6%for E.coli and 87.6%for S.aureus,while retaining the original high moisture permeability of cotton fabric.So GO/cotton fabric can resist the multiplication of bacteria.At the same time,GO can greatly improve the UV protection performance of cotton fabric used in garments.With increase of the GO concentration,the UV protection ability of composite fabric is enhanced.Finally,GO-Ag/cotton fabric sensors had stable NH3 gassensitive properties and good washing stability.In conclusion,these cotton fabric sensors with antibacterial properties,UV resistance and highly sensitive gas-sensitive properties have potential applications in wearable early warning devices and textile products.
基金support from the National Key Research and Development Program of China(Nos.2022YFB3805203 and 2021YFA1200302)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)the National Natural Science Foundation of China(Nos.22073021,92056204,21890381,and 21721002).
文摘Integration and synergy of the unique functions of different components have been developed into one of the most convenient and effective ways to construct the composite advanced materials with collective properties and improved performances.In this work,the mace-like tetrathiafulvalene-tetracyanoquinodimethane(TTF-TCNQ)/HKUST-1 composite structures with single single-crystalline TTF-TCNQ submicrorods covered by ordered HKUST-1 nanosheet arrays were successfully constructed by an efficient TTF-TCNQ seed-mediated growth approach.Impressively,thanks to the synergetic and complementary effects between TTF-TCNQ and HKUST-1,the sensors based on such mace-like TTF-TCNQ/HKUST-1 composite structures not only displayed an experimental detection limit of 10 part per billion(ppb)for NO_(2) detection,but also exhibited outstanding selectivity even if the concentration of the interfering gases was 10 times that of NO_(2).Meanwhile,good reproducibility and rapid response were also achieved.This work opens the avenue for creation of novel high-performance sensing materials for application in gas sensing.
