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Nanostructured ZnO sensor fabricated by successive ionic layer adsorption and reaction method for ammonia sensing application
摘要： ZnO thin films were deposited onto glass substrate for various deposition cycles by successive ionic layer adsorption and reaction method. Structural studies were confirmed that the films are polycrystalline with hexagonal wurtzite structure. SEM studies revealed the surface had closely packed spherical particles with pores. The transmission range was found to be above 75% and the band gap was calculated for all samples using optical studies. The changes in the oxidation state of ZnO thin film was studied using X-ray photoelectron spectroscopy. The chemical compositions of ZnO were confirmed by FTIR spectrum. The improved crystalline of ZnO thin film (50 cycles) has been chosen for the fabrication of ammonia vapour sensor. The vapour sensing behaviour of the film was observed for various concentrations of ammonia at an optimized operating temperature of 200oC. The lowest detection limit was found to be 1 ppm of ammonia vapour concentration.
关键词： Ammonia vapour,Sensing properties,SILAR,ZnO,topographical properties
更新于2025-09-23 15:22:29
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Effects of sintering temperature on sensing properties of WO <sub/>3</sub> and Ag-WO <sub/>3</sub> electrode for NO <sub/>2</sub> sensor
摘要： Pure WO3 and Ag-WO3 (mixed solid solutions Ag with WO3) have been successfully synthesized by sol-gel method and the influences of calcination temperature on the particle size, morphology of the WO3 and Ag-WO3 nanoparticles were investigated. Powder X-ray diffraction results show that the hexagonal to monoclinic phase transition occurs at calcination temperature varying from 300°C to 500°C. SEM images show that calcination temperature plays an important role in controlling the particle size and morphology of the as-prepared WO3 and Ag-WO3 nanoparticles. The NO2 gas sensing properties of the sensors based on WO3 and Ag-WO3 nanoparticles calcined at different temperatures were investigated and the experimental results exhibit that the gas sensing properties of the Ag-WO3 sensors were superior to those of the pure WO3. Especially, the sensor based on Ag-WO3 calcined at 500°C possessed larger response, better selectivity, faster response/recovery and better longer-term stability to NO2 than the others at relatively low operating temperature (150°C).
关键词： tungsten trioxide,sintering temperature,low operating temperature,gas sensing properties
更新于2025-09-11 14:15:04
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Synthesis of Sn-doped ZnO hierarchical particles and their gas-sensing properties
摘要： In this work, un-doped and Sn-doped hierarchical ZnO particles with high dispersity were successfully fabricated by a facile liquid reaction. The prepared samples are characterised by X-ray diffraction and scanning electron microscopy. The as-synthesised hierarchical ZnO particles with a diameter of ～1.5 μm were obtained by considerably intersecting thin nanosheets of ～20 nm thickness. The morphology of ZnO structures can be varied by adjusting reaction parameters, e.g. reaction temperature, calcination temperature, and dopant concentration. On the basis of experimental results, the gas-sensing measurement displays that the sensor based on Sn-doped ZnO microstructures have a low detection of 10 ppm ethanol at an operational temperature of 250°C, demonstrating its outstanding gas-sensing performance. Therefore, the ?ower-like Sn-doped ZnO have prospective applications in a multifunction ethanol sensor. Moreover, the fabrication method reported in the work is facile, ?exible and operable, it is possible to extend to synthesise other types of metal oxide-based applications in various ?elds.
关键词： Sn-doped ZnO,hierarchical particles,facile liquid reaction,gas-sensing properties,ethanol sensor
更新于2025-09-10 09:29:36