A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set t...A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect absorption.The first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner ERR.The second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric resonators.Furthermore,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding medium.The sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and Chloroform.High Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.展开更多
We designed and fabricated a smart microcavity sensor with a vertically coupled structure on the end face of a multi-core fiber using two-photon lithography technology. The influence of gap in vertical coupling struct...We designed and fabricated a smart microcavity sensor with a vertically coupled structure on the end face of a multi-core fiber using two-photon lithography technology. The influence of gap in vertical coupling structure on the resonance characteristics of bonding and anti-bonding modes in the transmission spectrum was studied through simulation and experiments. The results indicate that the bonding and anti-bonding modes generated by the vertical coupling of the two microcavities, as well as the changes in the radius and refractive index of the micro-toroid, and the distance between the microcavities caused by the absorption of vapor during the gas sensing process, exhibit different wavelength shifts for the two resonant modes. Smart microcavity sensors exhibit sensitivity and sensing characteristics. .展开更多
Looking toward world technology trends over the next few decades, self-powered sensing networks are a key field of technological and economic driver for global industries. Since 2006, Zhong Lin Wang's group has pr...Looking toward world technology trends over the next few decades, self-powered sensing networks are a key field of technological and economic driver for global industries. Since 2006, Zhong Lin Wang's group has proposed a novel concept of nanogenerators(NGs), including piezoelectric nanogenerator and triboelectric nanogenerator, which could convert a mechanical trigger into an electric output. Considering motion ubiquitously exists in the surrounding environment and for any most common materials used every day, NGs could be inherently served as an energy source for our daily increasing requirements or as one of self-powered environmental sensors. In this regard, by coupling the piezoelectric or triboelectric properties with semiconducting gas sensing characterization, a new research field of self-powered gas sensing has been proposed. Recent works have shown promising concept to realize NG-based self-powered gas sensors that are capable of detecting gas environment without the need of external power sources to activate the gas sensors or to actively generate a readout signal. Compared with conventional sensors, these self-powered gas sensors keep the approximate performance.Meanwhile, these sensors drastically reduce power consumption and additionally reduce the required space for integration,which are significantly suitable for the wearable devices. This paper gives a brief summary about the establishment and latest progress in the fundamental principle, updated progress and potential applications of NG-based self-powered gas sensing system. The development trend in this field is envisaged, and the basic configurations are also introduced.展开更多
A novel and efficient absorption line recovery technique is presented.A micro-electromechanical systems(MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirr...A novel and efficient absorption line recovery technique is presented.A micro-electromechanical systems(MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirror reflection.Tunable diode laser spectroscopy(TDLS) and photoacoustic spectroscopy(PAS) are used to recover the target absorption line profile which is compared with the theoretical Voigt profile.The target gas is 0.01% acetylene(C2H2) in a nitrogen host gas.The laser diode wavelength is swept across the P17 absorption line of acetylene at 1 535.4 nm by a current ramp,and an erbium-doped fibre amplifier(EDFA) is used to enhance the optical intensity and increase the signal-to-noise ratio(SNR).A SNR of about 35 is obtained with 100 mW laser power from the EDFA.Good agreement is achieved between the experimental results and the theoretical simulation for the P17 absorption line profile.展开更多
Molecular structure of organic semiconductor plays a critical role in determining the performance and functionality of organic electronic devices,by optimizing the electrical,optical and physicochemical properties.Sub...Molecular structure of organic semiconductor plays a critical role in determining the performance and functionality of organic electronic devices,by optimizing the electrical,optical and physicochemical properties.Substituted alkyl chains are fundamental units in tailering the solubility and assemblability,among which the asymmetric properties have been reported as key element for controlling the packing motifs and intrinsic charge transport.Here,we expanded the scope of molecular asymmetry dependent sensing features based on a new series of naphthalene diimides(NDI)-based derivatives substituted with a same branching alkyl chain but various linear-shaped alkyl chains(Cn-).A clear molecular stacking change,from head-to-head bilayer to head-to-tail monolayer packing model,is observed based on the features of anisotropic molecular interactions with the change in the chain length.Most importantly,a unique LUMO level shift of 0.17 eV is validated for NDI-PhC4,providing a record sensitivity up to 150%to 0.01 ppb ammonia,due to the desired molecular reactivity and device amplification properties.These results indicate that asymmetric side-chain engineering opens a route for breath healthcare.展开更多
In the field of absorption spectroscopy,the multipass cell[MPC]is one of the key elements.It has the advantages of simple structure,easy adjustment,and high spectral coverage,which is an effective way to improve the d...In the field of absorption spectroscopy,the multipass cell[MPC]is one of the key elements.It has the advantages of simple structure,easy adjustment,and high spectral coverage,which is an effective way to improve the detection sensitivity of gas sensing systems such as tunable diode laser absorption spectroscopy.This invited paper summarizes the design theory and the research results of some mainstream types of MPCs based on two mirrors and more than two mirrors in recent years,and briefly introduces the application of some processed products.The design theory of modified ABCD matrix and vector reflection principle are explained in detail.Finally,trends in its development are predicted.展开更多
The poor sensitivity of metal-oxide(MO)sensing material at room temperature can be enhanced by the modi-fication of noble metal catalysts.However,the large size and uncontrollable morphology of metal nanoparticles(NPs...The poor sensitivity of metal-oxide(MO)sensing material at room temperature can be enhanced by the modi-fication of noble metal catalysts.However,the large size and uncontrollable morphology of metal nanoparticles(NPs)compromise the catalytic activity and selectivity.Downsizing metal NPs to the atomic level is a promising solution because it offers high activity and selectivity.Nevertheless,a facile and universal approach for stable loading atomic-level metal on MO-based sensing materials is still challenging.Herein,we present a strategy to construct synergetic coordination interface for uniform loading of atomic-level metal catalysts on MO-based gas-sensing materials using a difunctional mediator layer.In this work,atomically dispersed Pt catalysts are coor-dinately anchored on ZnO nanorods(NRs)using polydopamine(PDA)as a mediator.As a result,compared with pristine ZnO NRs,a six-fold enhanced response of 18,489%is achieved toward 100 ppm NO_(2)on 0.20 wt%Pt-ZnO@PDA-1.5 nm,and the selectivity is also promoted.Such sensitivity is higher than that of most reported noble metal-modified MO NO_(2)-sensing materials.This work provides a simple and general strategy for building highly sensitive and selective gas-sensing materials using atomic-level noble metal catalyst.展开更多
Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction bet...Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction between high crystallinity and high surface area,the synthesis of mesoporous SMOs heterojunctions with highly o rdered mesostructures,highly crystallized frameworks,and high surface area remains a huge challenge.In this work,we develop a novel"acid-base pair"adjusted solvent evaporation induced self-assembly(EISA)strategy to prepare highly crystallized ordered mesoporous TiO2/WO3(OM-TiO2/WO3)heterojunctions.The WCl6 and titanium isopropoxide(TIPO)are used as the precursors,respectively,which function as the"acid-base pair",enabling the coassembly with the structure directing agent(PEO-b-PS)into highly ordered meso structures.In addition,PEO-b-PS can be converted to rigid carbon which can protect the meso structures from collapse during the crystallization process.The resultant OM-TiO2/WO3 heterojunctions possess primitive cubic mesostructures,large pore size(~21.1 nm),highly crystalline frameworks and surface area(~98 m2/g).As a sensor for acetone,the obtained OM-TiO2/WO3 show excellent re sponse/recovery perfo rmance(3 s/5 s),good linear dependence,repeatability,selectivity,and long-term stability(35 days).展开更多
Multi-component and multi-point trace gas sensing in the wavelength modulation spectroscopy is demonstrated based on the frequency-division multiplexing and time-division multiplexing technology.A reference photodetec...Multi-component and multi-point trace gas sensing in the wavelength modulation spectroscopy is demonstrated based on the frequency-division multiplexing and time-division multiplexing technology.A reference photodetector is connected in series with a reference gas cell with the constant concentration to measure the second-harmonics peak of the components for wavelength stabilization in real time.The central wavelengths of the distributed feedback lasers are locked to the target gas absorption centers by the reference second-harmonics signal using a digital proportional-integral-derivative controller.The distributed feedback lasers with different wavelengths and modulation frequencies are injected into the gas cell to achieve multi-components gas measurement by the frequency-division multiplexing technology.In addition,multi-point trace gas sensing is achieved by the time-division multiplexing technology using a photoswitch and a relay unit.We use this scheme to detect methane(CH4)at 1650.9 nm and water vapor(H2O)at 1368.597 nm as a proof of principle with the gas cell path length of 10 cm.The minimum detection limits achieved for H2O and CH4 are 1.13 ppm and 11.85 ppm respectively,with three-point gas cell measurement;thus 10.5-fold and 10.1-fold improvements are achieved in comparison with the traditional wavelength modulation spectroscopy.Meanwhile,their excellent R-square values reach 0.9983 and 0.99564 for the concentration ranges of 500 ppm to 2000 ppm and 800 ppm to 2700 ppm,respectively.展开更多
Novel nano-structured films of V2O5 are prepared by pulsed laser deposition method. Nanoscaled V2O5 ridges lie on SrTiO3 substrate and construct into grid-textured structures. Structural properties of the films have b...Novel nano-structured films of V2O5 are prepared by pulsed laser deposition method. Nanoscaled V2O5 ridges lie on SrTiO3 substrate and construct into grid-textured structures. Structural properties of the films have been analyzed by scanning electron microscope, X-ray diffraction and transmission electron microscope. The films have enlarged surface-to-volume ratio due to the ridge-channel structure which makes them applicable to gas sensing. Therefore, gas sensors based on the V2O5 films have been assembled which present reliable sensing properties to gaseous acetone, and ethanol at room temperature. The physical-chemical reactions between adsorbed O2^– and testing gases are the possible reason for this property.展开更多
Gas sensing for measurement of gas components, concentrations, and other parameters plays an important role in many fields. In this Letter, a micro-ring resonator laser used for gas sensing is experimentally demonstra...Gas sensing for measurement of gas components, concentrations, and other parameters plays an important role in many fields. In this Letter, a micro-ring resonator laser used for gas sensing is experimentally demonstrated. The multi-quantumwells micro-ring laser based on whispering-gallery modes with an annular resonator and an output waveguide was fabricated. A single-mode laser with a wavelength of 1746.4 nm was fabricated for the first time, to the best of our knowledge,experimentally. The output power of 1.65 m W under 40 m A injection current was obtained with a side-mode suppression ratio over 33 d B.展开更多
Ⅰ The Indexes of Detecting Oil and Gas Resources The deeply buried reservoir which in a dynamic equilibrium state has a great pressure inside, and between it and earth surface there is a great difference of pressure....Ⅰ The Indexes of Detecting Oil and Gas Resources The deeply buried reservoir which in a dynamic equilibrium state has a great pressure inside, and between it and earth surface there is a great difference of pressure. Therefore the hydrocarbon must spread and move vertically to the surface along the pressure gradient orientation. Hydrocarbons in the reservoir along some small rifts, cracks, joints and cleavages penetrate the overlying strata and seepage onto the surface. Thus the hydrocarbons become unvisble oil and gas signs. This process is called the phenomena of hydrocarbon microseepage of reservoir. Hydrocarbons microseepage in the process展开更多
A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manu...A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manuscript.An erbi-um-doped fiber amplifier(EDFA)was employed to amplify the output optical power so that the signal level was further enhanced.The optical path length(OPL)and the ratio of optical path length to volume(RLV)of the MPC is 37.7 m and 13.8 cm^(-2),respectively.A commercial QTF and a self-designed trapezoidal-tip QTF with low frequency of 9461.83 Hz were used as the detectors of the sensor,respectively.The target gas selected to test the performance of the system was acetylene(C2H2).When the optical power was constant at 1000 mW,the minimum detection limit(MDL)of the C2H2-LITES sensor can be achieved 48.3 ppb when using the commercial QTF and 24.6 ppb when using the trapezoid-al-tip QTF.An improvement of the detection performance by a factor of 1.96 was achieved after replacing the commer-cial QTF with the trapezoidal-tip QTF.展开更多
Molybdenum-based materials have been intensively investigated for high-performance gas sensor applications.Particularly,molybdenum oxides and dichalcogenides nanostructures have been widely examined due to their tunab...Molybdenum-based materials have been intensively investigated for high-performance gas sensor applications.Particularly,molybdenum oxides and dichalcogenides nanostructures have been widely examined due to their tunable structural and physicochemical properties that meet sensor requirements.These materials have good durability,are naturally abundant,low cost,and have facile preparation,allowing scalable fabrication to fulfill the growing demand of susceptible sensor devices.Significant advances have been made in recent decades to design and fabricate various molybdenum oxides-and dichalcogenides-based sensing materials,though it is still challenging to achieve high performances.Therefore,many experimental and theoretical investigations have been devoted to exploring suitable approaches which can significantly enhance their gas sensing properties.This review comprehensively examines recent advanced strategies to improve the nanostructured molybdenum-based material performance for detecting harmful pollutants,dangerous gases,or even exhaled breath monitoring.The summary and future challenges to advance their gas sensing performances will also be presented.展开更多
Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecti...Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecting different hazardous gases.TiO_(2) nanomaterials are promising candidates with great potential and excellent per-formance in gas sensor applications,such as hydrogen,acetone,ammonia,and ethanol detection.This review begins with a detailed discussion of the di ferent dimensional morphologies of TiO_(2),whitch affect the gas sensing performance of TiO_(2) sensors.The diverse morphologies of TiO_(2) can easily be tuned by regulating the manufacturing conditions.Meanwhile,they exhibit unique characteristics for detecting gases,including large specific suface area,superior elecron tr ansport rates,extraordinary pemmeability,and active reaction sites,which offer new opportunities to improve the gas sensing properties.In addition,a variety of efforts have been made to functional TiO_(2) nanomaterials to further enhance sensing properties,including TiO_(2)-based composites and light-assisted gas sensors.The enhanced gas sensing mechanisms of multi-component composite nano-materials based on TiO_(2) include loaded noble metals,doped elements,constructed heterojunctions,and com-pounded with other functional materials.Finally,several studies have been summarized to demonstate the compar ative sensing properties of TiO_(2)-based gas sensors.展开更多
The work reports the synthesis of nickel nanoparticles supported on thermally reduced graphene oxides(rGO)in the ionic liquid[BMIm][NTf_(2)]through microwave decomposition reaction.Ni@rGO with the polymer poly(3,4-eth...The work reports the synthesis of nickel nanoparticles supported on thermally reduced graphene oxides(rGO)in the ionic liquid[BMIm][NTf_(2)]through microwave decomposition reaction.Ni@rGO with the polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)as binder was positively tested for its response towards the oxidizing gas nitrogen dioxide(10 ppm in air),the reducing gas carbon monoxide(3000 ppm in N_(2))and the volatile organic compound(VOC)acetone(35,000 ppm in air).The results from different gases were compared at different temperatures with the best results for NO_(2) at 200℃.Additionally,it is shown for NO_(2) gas that the Ni@rGO-PEDOT:PSS polymer composite gives better results than the rGO-PEDOT:PSS polymer composite.After the heat treatment the oxidation state of pure nickel nanoparticles were confirmed by powder diffraction.展开更多
Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio.However,the poor response time and incomplete recovery re-strict their applicat...Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio.However,the poor response time and incomplete recovery re-strict their application in practical,high performance gas sensors.In this work,we fabricated air-stable ReS_(2)/GaSe heterostructure-based NO_(2)gas sensors with excellent gas sensing response,recovery,selectiv-ity and a low limit of detection(LOD)toward nitrogen dioxide(NO_(2)).The ReS_(2)/GaSe heterostructure was prepared via mechanical exfoliation and an all-dry transfer method.Before the sensing measurements,temperature-dependant transport measurements were carried out.The Schottky Barrier Height(SBH)of the ReS_(2)/GaSe heterostructure was calculated and the corresponding transport mechanisms were dis-cussed.The fabricated gas sensors showed a significant response enhancement with full reversibility to-ward ppm-level NO_(2)(response of∼17%at 3 ppm,a LOD of∼556 ppb)at an operating temperature of(33°C).In particular,the total response and recovery time of the ReS_(2)/GaSe was revealed to be less than 4 min(∼38 s and∼174 s,respectively)for the 250 ppm concentration,which is one of the best response and recovery time toward ppm-level NO_(2).The excellent sensing performances and recovery characteris-tics of the ReS_(2)/GaSe structure are attributed to its efficient charge separation,unique interlayer coupling and desirable band alignments.This atomically thin,ultrasensitive gas sensor that operates at room tem-perature is a strong technological contender to conventional metal oxide gas sensors,which often require elevated temperatures.展开更多
LaMnO_(3) modified Co_(3)O_(4) nanocomposites were prepared by simple hydrothermal method co mbined with sol-gel method.The gas sensitivity properties of pure Co_(3)O_(4) and LaMnO_(3)/Co_(3)O_(4) with different compo...LaMnO_(3) modified Co_(3)O_(4) nanocomposites were prepared by simple hydrothermal method co mbined with sol-gel method.The gas sensitivity properties of pure Co_(3)O_(4) and LaMnO_(3)/Co_(3)O_(4) with different composite proportions are compared.It is found that 0.6-LMO/Co_(3)O_(4) sensor has higher sensitivity to triethylamine(TEA)than pure Co_(3)O_(4) sensor,which is improved by 9.27 times.And the working temperature is reduced from 150 to 130℃.Besides,it has excellent gas selectivity and repeatability.The improvement of the gas sensitivity of LaMnO_(3)/Co_(3)O_(4) sensor may be due to the fact that LaMnO_(3) is an effective catalyst,and the catalytic performance perhaps is beneficial to improving the sensing performance.In addition,the formation of p-p heterojunctions may be the key factor to improve the gas sensing performance.This work provides a new Co_(3)O_(4)-based gas sensing material for the detection of TEA.展开更多
A wide wavelength tuning range and single-mode hybrid cavity laser consists of a square Whispering-Gallery(WG)microcavity and a Fabry–Pérot(FP)was introduced and demonstrated.A wavelength tuning range over 12.5 ...A wide wavelength tuning range and single-mode hybrid cavity laser consists of a square Whispering-Gallery(WG)microcavity and a Fabry–Pérot(FP)was introduced and demonstrated.A wavelength tuning range over 12.5 nm from 1760.87 to 1773.39 nm which was single-mode emitting was obtained with the side-mode suppression ratio over 30 dB.The hybrid cavity laser does not need grating etching and special epitaxial structure,which reduces the fabrication difficulty and cost,and shows the potential for gas sensing with absorption lines in this range.展开更多
There are urgent needs of volatile amine gas sensors with high-performance in food quality control,disease monitoring and environmental pollution.Thin-film fluorescent probe is suitable for amine vapour sensing due to...There are urgent needs of volatile amine gas sensors with high-performance in food quality control,disease monitoring and environmental pollution.Thin-film fluorescent probe is suitable for amine vapour sensing due to its high sensitivity,high selectivity,and no polluting analyte.Herein,a novel fluorescent probe based on indacenodithiophene structure withπconjugated system was designed and synthesized.The experimental results show that the films prepared by this material exhibit rapid and distinct fluorescence quenching after being exposed to saturated vapours of primary amine,secondary amine and tertiary amine represented by n-propylamine,diethylamine and trimethylamine,respectively.The quenching of fluorescence is 84%,87%and 96%,respectively,within 10 s.The detection mechanism of probe for primary amine is based on specific chemical reaction,while the detection mechanism for secondary amine and tertiary amine is intramolecular charge transfer.Further experiments show that the detection limit of the fluorescent probe for trimethylamine,an important marker of food spoilage,could reach 4.610 ppt.On-site detection based on spoilage of small yellow croaker suggests the material possesses the potential for food freshness detection.This simple fluorogenic probe is an original approach to simplify real-time visual monitoring of volatile amine vapour.展开更多
文摘A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect absorption.The first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner ERR.The second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric resonators.Furthermore,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding medium.The sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and Chloroform.High Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.
文摘We designed and fabricated a smart microcavity sensor with a vertically coupled structure on the end face of a multi-core fiber using two-photon lithography technology. The influence of gap in vertical coupling structure on the resonance characteristics of bonding and anti-bonding modes in the transmission spectrum was studied through simulation and experiments. The results indicate that the bonding and anti-bonding modes generated by the vertical coupling of the two microcavities, as well as the changes in the radius and refractive index of the micro-toroid, and the distance between the microcavities caused by the absorption of vapor during the gas sensing process, exhibit different wavelength shifts for the two resonant modes. Smart microcavity sensors exhibit sensitivity and sensing characteristics. .
基金supported by Natural Science Foundation of China(NSFC)(Grant No.U1432249)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)+1 种基金supported by Collaborative Innovation Center of Suzhou Nano Science&Technologysponsored by Qing Lan Project
文摘Looking toward world technology trends over the next few decades, self-powered sensing networks are a key field of technological and economic driver for global industries. Since 2006, Zhong Lin Wang's group has proposed a novel concept of nanogenerators(NGs), including piezoelectric nanogenerator and triboelectric nanogenerator, which could convert a mechanical trigger into an electric output. Considering motion ubiquitously exists in the surrounding environment and for any most common materials used every day, NGs could be inherently served as an energy source for our daily increasing requirements or as one of self-powered environmental sensors. In this regard, by coupling the piezoelectric or triboelectric properties with semiconducting gas sensing characterization, a new research field of self-powered gas sensing has been proposed. Recent works have shown promising concept to realize NG-based self-powered gas sensors that are capable of detecting gas environment without the need of external power sources to activate the gas sensors or to actively generate a readout signal. Compared with conventional sensors, these self-powered gas sensors keep the approximate performance.Meanwhile, these sensors drastically reduce power consumption and additionally reduce the required space for integration,which are significantly suitable for the wearable devices. This paper gives a brief summary about the establishment and latest progress in the fundamental principle, updated progress and potential applications of NG-based self-powered gas sensing system. The development trend in this field is envisaged, and the basic configurations are also introduced.
基金Financial support from National High Technology Research and Development Programof China(Grant No.:2007A A06Z1122007AA03Z446)
文摘A novel and efficient absorption line recovery technique is presented.A micro-electromechanical systems(MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirror reflection.Tunable diode laser spectroscopy(TDLS) and photoacoustic spectroscopy(PAS) are used to recover the target absorption line profile which is compared with the theoretical Voigt profile.The target gas is 0.01% acetylene(C2H2) in a nitrogen host gas.The laser diode wavelength is swept across the P17 absorption line of acetylene at 1 535.4 nm by a current ramp,and an erbium-doped fibre amplifier(EDFA) is used to enhance the optical intensity and increase the signal-to-noise ratio(SNR).A SNR of about 35 is obtained with 100 mW laser power from the EDFA.Good agreement is achieved between the experimental results and the theoretical simulation for the P17 absorption line profile.
基金financially supported by the National Natural Science Foundation of China(Nos.6197396,21905276)Natural Science Foundation of Beijing(No.4202077)+1 种基金Chinese Academy of Scinece(No.ZDBS-LY-SLH034)the Fundamental Research Funds for the Central Universities(No.E2ET0309X2)。
文摘Molecular structure of organic semiconductor plays a critical role in determining the performance and functionality of organic electronic devices,by optimizing the electrical,optical and physicochemical properties.Substituted alkyl chains are fundamental units in tailering the solubility and assemblability,among which the asymmetric properties have been reported as key element for controlling the packing motifs and intrinsic charge transport.Here,we expanded the scope of molecular asymmetry dependent sensing features based on a new series of naphthalene diimides(NDI)-based derivatives substituted with a same branching alkyl chain but various linear-shaped alkyl chains(Cn-).A clear molecular stacking change,from head-to-head bilayer to head-to-tail monolayer packing model,is observed based on the features of anisotropic molecular interactions with the change in the chain length.Most importantly,a unique LUMO level shift of 0.17 eV is validated for NDI-PhC4,providing a record sensitivity up to 150%to 0.01 ppb ammonia,due to the desired molecular reactivity and device amplification properties.These results indicate that asymmetric side-chain engineering opens a route for breath healthcare.
基金supported by the National Natural Science Foundation of China(Nos.62275065,62022032,and 61875047)Natural Science Foundation of Heilongjiang Province of China(No.YQ2019F006)。
文摘In the field of absorption spectroscopy,the multipass cell[MPC]is one of the key elements.It has the advantages of simple structure,easy adjustment,and high spectral coverage,which is an effective way to improve the detection sensitivity of gas sensing systems such as tunable diode laser absorption spectroscopy.This invited paper summarizes the design theory and the research results of some mainstream types of MPCs based on two mirrors and more than two mirrors in recent years,and briefly introduces the application of some processed products.The design theory of modified ABCD matrix and vector reflection principle are explained in detail.Finally,trends in its development are predicted.
基金supported by the National Natural Science Foundation of China(91961115,22171263,21975254,and 22271281)Scientific Research and Equipment Development Project of CAS(YJKYQ20210024)+2 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR101)the Natural Science Foundation of Fujian Province(2021J02017,2022J05088 and 2022J06032)CAS Pioneer Hundred Talents Program B(E2XBRD1).
文摘The poor sensitivity of metal-oxide(MO)sensing material at room temperature can be enhanced by the modi-fication of noble metal catalysts.However,the large size and uncontrollable morphology of metal nanoparticles(NPs)compromise the catalytic activity and selectivity.Downsizing metal NPs to the atomic level is a promising solution because it offers high activity and selectivity.Nevertheless,a facile and universal approach for stable loading atomic-level metal on MO-based sensing materials is still challenging.Herein,we present a strategy to construct synergetic coordination interface for uniform loading of atomic-level metal catalysts on MO-based gas-sensing materials using a difunctional mediator layer.In this work,atomically dispersed Pt catalysts are coor-dinately anchored on ZnO nanorods(NRs)using polydopamine(PDA)as a mediator.As a result,compared with pristine ZnO NRs,a six-fold enhanced response of 18,489%is achieved toward 100 ppm NO_(2)on 0.20 wt%Pt-ZnO@PDA-1.5 nm,and the selectivity is also promoted.Such sensitivity is higher than that of most reported noble metal-modified MO NO_(2)-sensing materials.This work provides a simple and general strategy for building highly sensitive and selective gas-sensing materials using atomic-level noble metal catalyst.
基金supported by the National Natural Science Foundation of China(Nos.51822202 and 51772050)China Postdoctoral Science Foundation(No.2019M651342)+2 种基金Shanghai Rising-Star Program(No.18QA1400100)Youth Top-notch Talent Support Program of Shanghai,the Shanghai Committee of Science and Technology,China(No.19520713200)DHU Distinguished Young Professor Program and Fundamental Research Funds for the Central Universities。
文摘Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction between high crystallinity and high surface area,the synthesis of mesoporous SMOs heterojunctions with highly o rdered mesostructures,highly crystallized frameworks,and high surface area remains a huge challenge.In this work,we develop a novel"acid-base pair"adjusted solvent evaporation induced self-assembly(EISA)strategy to prepare highly crystallized ordered mesoporous TiO2/WO3(OM-TiO2/WO3)heterojunctions.The WCl6 and titanium isopropoxide(TIPO)are used as the precursors,respectively,which function as the"acid-base pair",enabling the coassembly with the structure directing agent(PEO-b-PS)into highly ordered meso structures.In addition,PEO-b-PS can be converted to rigid carbon which can protect the meso structures from collapse during the crystallization process.The resultant OM-TiO2/WO3 heterojunctions possess primitive cubic mesostructures,large pore size(~21.1 nm),highly crystalline frameworks and surface area(~98 m2/g).As a sensor for acetone,the obtained OM-TiO2/WO3 show excellent re sponse/recovery perfo rmance(3 s/5 s),good linear dependence,repeatability,selectivity,and long-term stability(35 days).
基金This work was supported by the Research Fund for the Doctoral Program of Liao Cheng University(Grant No.318051543)and the National Natural Science Foundation of China(Grant No.61475085).
文摘Multi-component and multi-point trace gas sensing in the wavelength modulation spectroscopy is demonstrated based on the frequency-division multiplexing and time-division multiplexing technology.A reference photodetector is connected in series with a reference gas cell with the constant concentration to measure the second-harmonics peak of the components for wavelength stabilization in real time.The central wavelengths of the distributed feedback lasers are locked to the target gas absorption centers by the reference second-harmonics signal using a digital proportional-integral-derivative controller.The distributed feedback lasers with different wavelengths and modulation frequencies are injected into the gas cell to achieve multi-components gas measurement by the frequency-division multiplexing technology.In addition,multi-point trace gas sensing is achieved by the time-division multiplexing technology using a photoswitch and a relay unit.We use this scheme to detect methane(CH4)at 1650.9 nm and water vapor(H2O)at 1368.597 nm as a proof of principle with the gas cell path length of 10 cm.The minimum detection limits achieved for H2O and CH4 are 1.13 ppm and 11.85 ppm respectively,with three-point gas cell measurement;thus 10.5-fold and 10.1-fold improvements are achieved in comparison with the traditional wavelength modulation spectroscopy.Meanwhile,their excellent R-square values reach 0.9983 and 0.99564 for the concentration ranges of 500 ppm to 2000 ppm and 800 ppm to 2700 ppm,respectively.
基金supported by the National Key Project for Basic Research(Grant No.2014CB921002)the National Natural Science Foundation of China(Grant No.11374225)the Research Grant Council of Hong Kong(Grant No.702112)
文摘Novel nano-structured films of V2O5 are prepared by pulsed laser deposition method. Nanoscaled V2O5 ridges lie on SrTiO3 substrate and construct into grid-textured structures. Structural properties of the films have been analyzed by scanning electron microscope, X-ray diffraction and transmission electron microscope. The films have enlarged surface-to-volume ratio due to the ridge-channel structure which makes them applicable to gas sensing. Therefore, gas sensors based on the V2O5 films have been assembled which present reliable sensing properties to gaseous acetone, and ethanol at room temperature. The physical-chemical reactions between adsorbed O2^– and testing gases are the possible reason for this property.
基金supported by the National Key Research and Development Project (Nos. 2017YFB0405300 and 2018YFA0209001)National Natural Science Foundation of China (NSFC) (Nos. 61934007 and 61974141)Beijing MunicipalScienceandTechnologyProject(Nos. Z191100004819011 and 4182064)。
文摘Gas sensing for measurement of gas components, concentrations, and other parameters plays an important role in many fields. In this Letter, a micro-ring resonator laser used for gas sensing is experimentally demonstrated. The multi-quantumwells micro-ring laser based on whispering-gallery modes with an annular resonator and an output waveguide was fabricated. A single-mode laser with a wavelength of 1746.4 nm was fabricated for the first time, to the best of our knowledge,experimentally. The output power of 1.65 m W under 40 m A injection current was obtained with a side-mode suppression ratio over 33 d B.
文摘Ⅰ The Indexes of Detecting Oil and Gas Resources The deeply buried reservoir which in a dynamic equilibrium state has a great pressure inside, and between it and earth surface there is a great difference of pressure. Therefore the hydrocarbon must spread and move vertically to the surface along the pressure gradient orientation. Hydrocarbons in the reservoir along some small rifts, cracks, joints and cleavages penetrate the overlying strata and seepage onto the surface. Thus the hydrocarbons become unvisble oil and gas signs. This process is called the phenomena of hydrocarbon microseepage of reservoir. Hydrocarbons microseepage in the process
基金National Natural Science Foundation of China(Grant Nos.62335006,62022032,62275065,and 61875047)Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University),Ministry of Education(Grant No.OEIAM202202)Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023011).
文摘A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manuscript.An erbi-um-doped fiber amplifier(EDFA)was employed to amplify the output optical power so that the signal level was further enhanced.The optical path length(OPL)and the ratio of optical path length to volume(RLV)of the MPC is 37.7 m and 13.8 cm^(-2),respectively.A commercial QTF and a self-designed trapezoidal-tip QTF with low frequency of 9461.83 Hz were used as the detectors of the sensor,respectively.The target gas selected to test the performance of the system was acetylene(C2H2).When the optical power was constant at 1000 mW,the minimum detection limit(MDL)of the C2H2-LITES sensor can be achieved 48.3 ppb when using the commercial QTF and 24.6 ppb when using the trapezoid-al-tip QTF.An improvement of the detection performance by a factor of 1.96 was achieved after replacing the commer-cial QTF with the trapezoidal-tip QTF.
基金partly supported by the JSPS Grant-in-Aid for Scientific Research(No.JP16H06439,No.20H00297)by the Dynamic Alliance for Open Innovation Bridging Human,Environment and Materials in Network Joint Research Center for Materialsfinancial grants provided by Indonesia Ministry of Education,Culture,Research,and Technology,under the scheme of Basic Research Program No.2/E1/KP.PTNBH/2021 managed by Institut Teknologi Bandung。
文摘Molybdenum-based materials have been intensively investigated for high-performance gas sensor applications.Particularly,molybdenum oxides and dichalcogenides nanostructures have been widely examined due to their tunable structural and physicochemical properties that meet sensor requirements.These materials have good durability,are naturally abundant,low cost,and have facile preparation,allowing scalable fabrication to fulfill the growing demand of susceptible sensor devices.Significant advances have been made in recent decades to design and fabricate various molybdenum oxides-and dichalcogenides-based sensing materials,though it is still challenging to achieve high performances.Therefore,many experimental and theoretical investigations have been devoted to exploring suitable approaches which can significantly enhance their gas sensing properties.This review comprehensively examines recent advanced strategies to improve the nanostructured molybdenum-based material performance for detecting harmful pollutants,dangerous gases,or even exhaled breath monitoring.The summary and future challenges to advance their gas sensing performances will also be presented.
基金National Natural Science Foundation of China(No.61761047 and 41876055)the Yunnan Provincial Depart-ment of Science and Technology through the Key Project for the Science and Technology(Grant No.2017FA025)Program for hnovative Research Team(in Science and Technology)in University of Yunnan Province.
文摘Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecting different hazardous gases.TiO_(2) nanomaterials are promising candidates with great potential and excellent per-formance in gas sensor applications,such as hydrogen,acetone,ammonia,and ethanol detection.This review begins with a detailed discussion of the di ferent dimensional morphologies of TiO_(2),whitch affect the gas sensing performance of TiO_(2) sensors.The diverse morphologies of TiO_(2) can easily be tuned by regulating the manufacturing conditions.Meanwhile,they exhibit unique characteristics for detecting gases,including large specific suface area,superior elecron tr ansport rates,extraordinary pemmeability,and active reaction sites,which offer new opportunities to improve the gas sensing properties.In addition,a variety of efforts have been made to functional TiO_(2) nanomaterials to further enhance sensing properties,including TiO_(2)-based composites and light-assisted gas sensors.The enhanced gas sensing mechanisms of multi-component composite nano-materials based on TiO_(2) include loaded noble metals,doped elements,constructed heterojunctions,and com-pounded with other functional materials.Finally,several studies have been summarized to demonstate the compar ative sensing properties of TiO_(2)-based gas sensors.
文摘The work reports the synthesis of nickel nanoparticles supported on thermally reduced graphene oxides(rGO)in the ionic liquid[BMIm][NTf_(2)]through microwave decomposition reaction.Ni@rGO with the polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)as binder was positively tested for its response towards the oxidizing gas nitrogen dioxide(10 ppm in air),the reducing gas carbon monoxide(3000 ppm in N_(2))and the volatile organic compound(VOC)acetone(35,000 ppm in air).The results from different gases were compared at different temperatures with the best results for NO_(2) at 200℃.Additionally,it is shown for NO_(2) gas that the Ni@rGO-PEDOT:PSS polymer composite gives better results than the rGO-PEDOT:PSS polymer composite.After the heat treatment the oxidation state of pure nickel nanoparticles were confirmed by powder diffraction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)(No.2018R1A6A1A03025708)supported by the Nano-Material Technology Development Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Science,ICT and Future Planning(No.2009-0082580).
文摘Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio.However,the poor response time and incomplete recovery re-strict their application in practical,high performance gas sensors.In this work,we fabricated air-stable ReS_(2)/GaSe heterostructure-based NO_(2)gas sensors with excellent gas sensing response,recovery,selectiv-ity and a low limit of detection(LOD)toward nitrogen dioxide(NO_(2)).The ReS_(2)/GaSe heterostructure was prepared via mechanical exfoliation and an all-dry transfer method.Before the sensing measurements,temperature-dependant transport measurements were carried out.The Schottky Barrier Height(SBH)of the ReS_(2)/GaSe heterostructure was calculated and the corresponding transport mechanisms were dis-cussed.The fabricated gas sensors showed a significant response enhancement with full reversibility to-ward ppm-level NO_(2)(response of∼17%at 3 ppm,a LOD of∼556 ppb)at an operating temperature of(33°C).In particular,the total response and recovery time of the ReS_(2)/GaSe was revealed to be less than 4 min(∼38 s and∼174 s,respectively)for the 250 ppm concentration,which is one of the best response and recovery time toward ppm-level NO_(2).The excellent sensing performances and recovery characteris-tics of the ReS_(2)/GaSe structure are attributed to its efficient charge separation,unique interlayer coupling and desirable band alignments.This atomically thin,ultrasensitive gas sensor that operates at room tem-perature is a strong technological contender to conventional metal oxide gas sensors,which often require elevated temperatures.
基金Project supported by the Shandong Natural Science Foundation(ZR2019BF030,ZR2019BEM036)。
文摘LaMnO_(3) modified Co_(3)O_(4) nanocomposites were prepared by simple hydrothermal method co mbined with sol-gel method.The gas sensitivity properties of pure Co_(3)O_(4) and LaMnO_(3)/Co_(3)O_(4) with different composite proportions are compared.It is found that 0.6-LMO/Co_(3)O_(4) sensor has higher sensitivity to triethylamine(TEA)than pure Co_(3)O_(4) sensor,which is improved by 9.27 times.And the working temperature is reduced from 150 to 130℃.Besides,it has excellent gas selectivity and repeatability.The improvement of the gas sensitivity of LaMnO_(3)/Co_(3)O_(4) sensor may be due to the fact that LaMnO_(3) is an effective catalyst,and the catalytic performance perhaps is beneficial to improving the sensing performance.In addition,the formation of p-p heterojunctions may be the key factor to improve the gas sensing performance.This work provides a new Co_(3)O_(4)-based gas sensing material for the detection of TEA.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2018YFA0209001)the Key Project of Frontier Science Research Project of CAS(Grant No.QYZDY-SSW-JSC021)the Strategic Priority Research Program of CAS(Grant No.XDB43020202).
文摘A wide wavelength tuning range and single-mode hybrid cavity laser consists of a square Whispering-Gallery(WG)microcavity and a Fabry–Pérot(FP)was introduced and demonstrated.A wavelength tuning range over 12.5 nm from 1760.87 to 1773.39 nm which was single-mode emitting was obtained with the side-mode suppression ratio over 30 dB.The hybrid cavity laser does not need grating etching and special epitaxial structure,which reduces the fabrication difficulty and cost,and shows the potential for gas sensing with absorption lines in this range.
基金supported by the National Key Research and Development Program of China(No.2022YFB3203500)the National Natural Science Foundation of China(Nos.62022085,61831021)the Science and Technology Commission of Shanghai Municipality(No.22QA1410800)。
文摘There are urgent needs of volatile amine gas sensors with high-performance in food quality control,disease monitoring and environmental pollution.Thin-film fluorescent probe is suitable for amine vapour sensing due to its high sensitivity,high selectivity,and no polluting analyte.Herein,a novel fluorescent probe based on indacenodithiophene structure withπconjugated system was designed and synthesized.The experimental results show that the films prepared by this material exhibit rapid and distinct fluorescence quenching after being exposed to saturated vapours of primary amine,secondary amine and tertiary amine represented by n-propylamine,diethylamine and trimethylamine,respectively.The quenching of fluorescence is 84%,87%and 96%,respectively,within 10 s.The detection mechanism of probe for primary amine is based on specific chemical reaction,while the detection mechanism for secondary amine and tertiary amine is intramolecular charge transfer.Further experiments show that the detection limit of the fluorescent probe for trimethylamine,an important marker of food spoilage,could reach 4.610 ppt.On-site detection based on spoilage of small yellow croaker suggests the material possesses the potential for food freshness detection.This simple fluorogenic probe is an original approach to simplify real-time visual monitoring of volatile amine vapour.