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
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
Unique coral-like ZnFe_(2)O_(4)-ZnO heterojunction architectures with abundant mesopores are successfully prepared via a facile two-step process.The as-fabricated ZnFe_(2)O_(4)-ZnO heterojunction architecture sensor i...Unique coral-like ZnFe_(2)O_(4)-ZnO heterojunction architectures with abundant mesopores are successfully prepared via a facile two-step process.The as-fabricated ZnFe_(2)O_(4)-ZnO heterojunction architecture sensor is used for the detection of the volatile organic compound triethylamine(TEA).The gas sensing performance of the as-prepared sensor is carefully investigated and the results show high response value,fast response/recovery times,good repeatability,and superior selectivity with regard to TEA detection.Specifically,the sensing response of the ZnFe_(2)O_(4)-ZnO sensor is remarkably improved and shows a fast response time of 0.9 s.The enhanced sensing mechanism of the coral-like mesoporous heterojunction architectures is discussed and a possible growth mechanism is also proposed.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.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funded by the Postdoctoral Science Foundation of China(801181040414)the National Natural Science Foundation of China(51875249 and 91963101).
文摘Unique coral-like ZnFe_(2)O_(4)-ZnO heterojunction architectures with abundant mesopores are successfully prepared via a facile two-step process.The as-fabricated ZnFe_(2)O_(4)-ZnO heterojunction architecture sensor is used for the detection of the volatile organic compound triethylamine(TEA).The gas sensing performance of the as-prepared sensor is carefully investigated and the results show high response value,fast response/recovery times,good repeatability,and superior selectivity with regard to TEA detection.Specifically,the sensing response of the ZnFe_(2)O_(4)-ZnO sensor is remarkably improved and shows a fast response time of 0.9 s.The enhanced sensing mechanism of the coral-like mesoporous heterojunction architectures is discussed and a possible growth mechanism is also proposed.
