In this paper, composite film based on polyvinylpyrrolidone(PVP)/graphene oxide(GO) was fabricated by spray method on AT-cut 9.986 MHz quartz crystal microbalance(QCM) for NH_3 sensing. The thin films were characteriz...In this paper, composite film based on polyvinylpyrrolidone(PVP)/graphene oxide(GO) was fabricated by spray method on AT-cut 9.986 MHz quartz crystal microbalance(QCM) for NH_3 sensing. The thin films were characterized by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR) and ultraviolet-visible spectroscopy(UV-VIS) to investigate the morphologies and the composition contents, respectively. The experimental results reveal that PVP/GO based sensor holds higher sensitivity, larger responsiveness and smaller baseline drift than those based on pure PVP at room temperature. Besides, the prepared sensor exhibits greater response to NH_3 than other gases such as CO, CO_2 and NO_2 at the same concentration. The good linearity, reproducibility and stability demonstrate the practicability of PVP/GO hybrid film in detecting NH_3.展开更多
Flexible nitrogen dioxide(NO_2) gas sensors based on organic thin-film transistors(OTFTs) were developed in this work, in which conductive indium tin oxide(ITO) coated polyethylene naphthalene-2,6-dicarboxylate(PEN) w...Flexible nitrogen dioxide(NO_2) gas sensors based on organic thin-film transistors(OTFTs) were developed in this work, in which conductive indium tin oxide(ITO) coated polyethylene naphthalene-2,6-dicarboxylate(PEN) was designed for the flexible substrates, and poly methyl methacrylate(PMMA) and poly(3-hexylthiophene)(P3HT) was spin-coated as the gate dielectric layer and spray-deposited as the active layer, respectively. The effects of PMMA concentrations and P3HT solution volume on performances of flexible OTFTs were systematically investigated. The results showed that the optimized flexible OTFT exhibited high field-effect mobility(9.51×10^(–3) cm^2/(V s) at a gate bias of –50 V) and excellent response characteristics,including high sensitivity(up to 0.169 ppm^(–1)), good repeatability and selectivity. The flexibility of the developed OTFT sensor was also investigated, and the results showed that the electrical and gas-sensing properties were affected by the bending cycles,thus further work should be done for improving the flexibility of the sensor. This work provides an effective approach in developing high performance flexible OTFT NO_2 gas sensor.展开更多
Formaldehyde(HCHO),a colorless and pungent-smelling gas,is confirmed be a huge threat to human health.The detection of formaldehyde is necessary and important.The Poly(3-hexythiophene)(P3HT)/ZnO organic-inorganic comp...Formaldehyde(HCHO),a colorless and pungent-smelling gas,is confirmed be a huge threat to human health.The detection of formaldehyde is necessary and important.The Poly(3-hexythiophene)(P3HT)/ZnO organic-inorganic composite thin film was fabricated and used as the sensitive layer of organic thin film transistors(OTFT) by spray-deposited method to detect HCHO at room temperature.The process parameters such as P3HT/ZnO weight ratios and airbrushed masses were optimized.The results showed that P3HT/ZnO OTFT exhibited good sensing response to HCHO.Airbrushed mass of 1ml was the optimal mass,and the 1:1 and 1:5 weight ratios of P3HT/ZnO exhibited better sensing properties compared with others.OTFT gas sensors based on P3HT/ZnO composite film provides a novel promising approach to the detection of HCHO.展开更多
A carbon monoxide gas sensor based on single-walled carbon nanotube （SWCNT） has been developed for detection of carbon monoxide （CO） at room temperature. Copper chloride （CuC1） was mixed with SWNT by mechanical ...A carbon monoxide gas sensor based on single-walled carbon nanotube （SWCNT） has been developed for detection of carbon monoxide （CO） at room temperature. Copper chloride （CuC1） was mixed with SWNT by mechanical blending. The thin film was deposited on interdigitated electrodes by using airbrush technology. This paper described the fabrication of the sensor for detecting carbon monoxide with concentrations from 20 ppm to 100 ppm. The performance of CO gas sensor was measured by using relevant apparatus to obtain the continuous sensor electric resistance change on exposure to CO and air atmosphere at room temperature, respectively. The results exhibited that the senor presented a larger sensitivity and a good recoverability. The experimental results suggested the potential use of CuC1 doped SWCNT for CO detecting.展开更多
A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insig...A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insight into the adsorption behaviors of gas molecules on the surface of ZnO nanocrystals under UV irradiation. The chemisorbed oxygen species(O^-2(ads)(hv)) induced by UV light govern the adsorption and desorption ways of other gas molecules on the surface of ZnO nanocrystals, which is dependent on the electron affinity of gas molecules. Gas molecules with higher electron affinity than oxygen molecules can be adsorbed on the surface by the competitive adsorption way, extracting electrons from the surface. Gas molecules with lower electron affinity than oxygen molecules are attracted by the adsorbed O^-2(ads)(hv)layer, releasing electrons to the surface. These processes can influence the gas sensing properties of the sensor. Our findings will pave the way for the fundamental understanding and design of UV-activated gas sensor in the future.展开更多
In this paper,bottom contact organic thin-film transistor(OTFT)gas sensors were prepared.Silicon dioxide(SiO2)and titanium/aurum(Ti/Au)were used as the insulating layer and the electrode for the device,respectively.Th...In this paper,bottom contact organic thin-film transistor(OTFT)gas sensors were prepared.Silicon dioxide(SiO2)and titanium/aurum(Ti/Au)were used as the insulating layer and the electrode for the device,respectively.The multi-walled carbon nanotubes(MWCNTs)/α-sexithiophene(α-6T)bilayer films were used as the active layer,andα-6T single layer sensitive film was also prepared for comparison purpose.The electrical and trace NO2-sening properties of these two OTFT gas sensors were tested and analyzed.The results showed that,the OTFT device based on MWCNTs/α-6T bilayer had obviously better electrical properties,better stabilities and higher NO2-sening response values than the device withα-6T single layer,in which both the carrier mobility(μ)and on/off current ratio enhanced two order of magnitude.The improved performance of bilayer OTFT can be explained that MWCNTs acted as highly conducting bridges connecting the crystalline terraces in theα-6T film.Threshold voltage(VT),carrier mobility,on/off current ratio and grid current which showed extremely similar variation trend as source-drain current,were optional parameters to reveal the gas-sensing characteristic of OTFT gas sensors.Morphology analysis showed that the special feature of MWCNTs had certain influence on the gas-sensing properties.展开更多
基金supported by the Funds for Creative Research Groups of China(Grant No.61421002)the National Natural Science Foundation of China(Grant No.61571097)
文摘In this paper, composite film based on polyvinylpyrrolidone(PVP)/graphene oxide(GO) was fabricated by spray method on AT-cut 9.986 MHz quartz crystal microbalance(QCM) for NH_3 sensing. The thin films were characterized by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR) and ultraviolet-visible spectroscopy(UV-VIS) to investigate the morphologies and the composition contents, respectively. The experimental results reveal that PVP/GO based sensor holds higher sensitivity, larger responsiveness and smaller baseline drift than those based on pure PVP at room temperature. Besides, the prepared sensor exhibits greater response to NH_3 than other gases such as CO, CO_2 and NO_2 at the same concentration. The good linearity, reproducibility and stability demonstrate the practicability of PVP/GO hybrid film in detecting NH_3.
基金supported by the Funds for Creative Research Groups of China(Grant No.61421002)the National Natural Science Foundation of China(Grant Nos.61571097 and 61604033)the National Postdoctoral Program for Innovative Talents(Grant No.BX201600026)
文摘Flexible nitrogen dioxide(NO_2) gas sensors based on organic thin-film transistors(OTFTs) were developed in this work, in which conductive indium tin oxide(ITO) coated polyethylene naphthalene-2,6-dicarboxylate(PEN) was designed for the flexible substrates, and poly methyl methacrylate(PMMA) and poly(3-hexylthiophene)(P3HT) was spin-coated as the gate dielectric layer and spray-deposited as the active layer, respectively. The effects of PMMA concentrations and P3HT solution volume on performances of flexible OTFTs were systematically investigated. The results showed that the optimized flexible OTFT exhibited high field-effect mobility(9.51×10^(–3) cm^2/(V s) at a gate bias of –50 V) and excellent response characteristics,including high sensitivity(up to 0.169 ppm^(–1)), good repeatability and selectivity. The flexibility of the developed OTFT sensor was also investigated, and the results showed that the electrical and gas-sensing properties were affected by the bending cycles,thus further work should be done for improving the flexibility of the sensor. This work provides an effective approach in developing high performance flexible OTFT NO_2 gas sensor.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61176066,61101031)
文摘Formaldehyde(HCHO),a colorless and pungent-smelling gas,is confirmed be a huge threat to human health.The detection of formaldehyde is necessary and important.The Poly(3-hexythiophene)(P3HT)/ZnO organic-inorganic composite thin film was fabricated and used as the sensitive layer of organic thin film transistors(OTFT) by spray-deposited method to detect HCHO at room temperature.The process parameters such as P3HT/ZnO weight ratios and airbrushed masses were optimized.The results showed that P3HT/ZnO OTFT exhibited good sensing response to HCHO.Airbrushed mass of 1ml was the optimal mass,and the 1:1 and 1:5 weight ratios of P3HT/ZnO exhibited better sensing properties compared with others.OTFT gas sensors based on P3HT/ZnO composite film provides a novel promising approach to the detection of HCHO.
基金supported by the National Natural Science Foundation of China(Grant Nos.61176066,61101031)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120185110012)
文摘A carbon monoxide gas sensor based on single-walled carbon nanotube （SWCNT） has been developed for detection of carbon monoxide （CO） at room temperature. Copper chloride （CuC1） was mixed with SWNT by mechanical blending. The thin film was deposited on interdigitated electrodes by using airbrush technology. This paper described the fabrication of the sensor for detecting carbon monoxide with concentrations from 20 ppm to 100 ppm. The performance of CO gas sensor was measured by using relevant apparatus to obtain the continuous sensor electric resistance change on exposure to CO and air atmosphere at room temperature, respectively. The results exhibited that the senor presented a larger sensitivity and a good recoverability. The experimental results suggested the potential use of CuC1 doped SWCNT for CO detecting.
基金supported by the Funds for Creative Research Groups of China(Grant No.61421002)the National Natural Science Foundation of China(Grant Nos.61571097,61604033,61671115)the National Postdoctoral Program for Innovative Talents(Grant No.BX201600026)
文摘A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insight into the adsorption behaviors of gas molecules on the surface of ZnO nanocrystals under UV irradiation. The chemisorbed oxygen species(O^-2(ads)(hv)) induced by UV light govern the adsorption and desorption ways of other gas molecules on the surface of ZnO nanocrystals, which is dependent on the electron affinity of gas molecules. Gas molecules with higher electron affinity than oxygen molecules can be adsorbed on the surface by the competitive adsorption way, extracting electrons from the surface. Gas molecules with lower electron affinity than oxygen molecules are attracted by the adsorbed O^-2(ads)(hv)layer, releasing electrons to the surface. These processes can influence the gas sensing properties of the sensor. Our findings will pave the way for the fundamental understanding and design of UV-activated gas sensor in the future.
基金supported by the Natural Natural Science Foundation of China(Grant Nos.61176066,61101031)
文摘In this paper,bottom contact organic thin-film transistor(OTFT)gas sensors were prepared.Silicon dioxide(SiO2)and titanium/aurum(Ti/Au)were used as the insulating layer and the electrode for the device,respectively.The multi-walled carbon nanotubes(MWCNTs)/α-sexithiophene(α-6T)bilayer films were used as the active layer,andα-6T single layer sensitive film was also prepared for comparison purpose.The electrical and trace NO2-sening properties of these two OTFT gas sensors were tested and analyzed.The results showed that,the OTFT device based on MWCNTs/α-6T bilayer had obviously better electrical properties,better stabilities and higher NO2-sening response values than the device withα-6T single layer,in which both the carrier mobility(μ)and on/off current ratio enhanced two order of magnitude.The improved performance of bilayer OTFT can be explained that MWCNTs acted as highly conducting bridges connecting the crystalline terraces in theα-6T film.Threshold voltage(VT),carrier mobility,on/off current ratio and grid current which showed extremely similar variation trend as source-drain current,were optional parameters to reveal the gas-sensing characteristic of OTFT gas sensors.Morphology analysis showed that the special feature of MWCNTs had certain influence on the gas-sensing properties.
