C2H5OH and NO2 sensing properties of ZnO nanostructures: correlation between crystal size, defect level and sensing performance

Quy, Chu Thi; Thai, Nguyen Xuan; Hòa, Nguyễn Đức; Le, Dang Thi Thanh; Hung, Chu Manh; Duy, Nguyễn Văn; Hiếu, Nguyễn Văn

doi:10.1039/c7ra13702h

Cited by 61 publications

(22 citation statements)

References 45 publications

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“…The main diffraction peaks implied that produced powders were highly single-phase hexagonal wurtzite structure, with average crystal size being 27.11 nm and lattice constants of a = 0.3249 nm and c = 0.5212 nm. This result is in the good agreement with JCPDS 36-1451 card [4]. There was no other peak of impurities observed.…”

Section: Chemicals and Fabrication Processsupporting

confidence: 89%

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

Xuan

2019

MaP

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This work reports photoluminescence evolution of hydrothermally homogeneous ZnO nanorods under thermal annealing at various temperatures. The crystalline structure and morphology of synthesized samples were characterized by X-ray diffractometry and Scanning electron microscopy. The optical properties which induced defect state transition were investigated by photoluminescence emission. Besides defect states induced emissions in the visible range, the photocatalytic activity of annealed samples was evaluated which indicated that the higher visible photoluminescence intensity gives the better catalytic activity.

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Section: Chemicals and Fabrication Processsupporting

confidence: 89%

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

Xuan

2019

MaP

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“…Furthermore, the resistance values of the ZnO NW sensors were considerably higher than those of the ZnO NR sensors. This finding was attributed to the smaller diameters of the NWs compared with the NRs [33,41]. Here, the diameter of the NWs was approximately twice the Debye length, whereas the diameter of the NRs was much larger than the Debye length.…”

Section: Resultsmentioning

confidence: 87%

New Design of ZnO Nanorod- and Nanowire-Based NO₂ Room-Temperature Sensors Prepared by Hydrothermal Method

Duoc

Hòa

et al. 2019

Journal of Nanomaterials

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Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

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“…Further peaks in the PL spectrum are associated with the presence of certain structural defects in the oxide. In both forms of ZnO, oxygen vacancies and oxygen atoms were found in interstitial positions [39,40]. In case of microrods, oxygen vacancies are clearly the dominant defect, whereas in case of ZnO powder, interstitial oxygen is the dominant defect (Figure 7).…”

Section: Structural Characterisationmentioning

confidence: 99%

Correlation between Microstructure and Chemical Composition of Zinc Oxide Gas Sensor Layers and Their Gas-Sensitive Properties in Chlorine Atmosphere

Fiedot‐Toboła¹,

Suchorska-Woźniak²,

Startek³

et al. 2020

Preprint

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In the article we present the results concerning the impact of structural and chemical properties of zinc oxide in various morphological forms, on its gas-sensitive properties tested in an atmosphere containing a very aggressive gas such as chlorine. Two types of ZnO sensor layers obtained by two different technological methods were used. Their morphology, crystal structure, specific surface area, porosity, surface chemistry and structural defects were characterized, and then compared with gas-sensitive properties in a chlorine-containing atmosphere. To achieve this goal scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL) methods were used. The sensing properties of obtained active layers were tested by temperature stimulated conductance method (TSC). We have noticed that their response in chlorine atmosphere is not determined by the size of the specific surface or porosity. The obtained results showed that the structural defects of ZnO crystals play the most important role in chlorine detection. We demonstrated that the Cl2 adsorption is a concurrent process to oxygen adsorption. Both of them occur on the same active species (oxygen vacancies). They concentration is higher on the side planes of the zinc oxide crystal than the others. Thanks to the conducted studies authors demonstrated that to develop a new gas sensor devices not only changing of active layer chemical composition but also controlling its crystal structure and morphology could be used.

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C₂H₅OH and NO₂ sensing properties of ZnO nanostructures: correlation between crystal size, defect level and sensing performance

Abstract: ZnO nanostructures were synthesized for ethanol and nitrogen dioxide gas-sensing applications. Results pointed out that the defect levels dominating the gas-sensing performance but not the morphology, specific surface area or crystal size.

Cited by 61 publications

References 45 publications

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

New Design of ZnO Nanorod- and Nanowire-Based NO₂ Room-Temperature Sensors Prepared by Hydrothermal Method

Correlation between Microstructure and Chemical Composition of Zinc Oxide Gas Sensor Layers and Their Gas-Sensitive Properties in Chlorine Atmosphere

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C2H5OH and NO2 sensing properties of ZnO nanostructures: correlation between crystal size, defect level and sensing performance

Abstract: ZnO nanostructures were synthesized for ethanol and nitrogen dioxide gas-sensing applications. Results pointed out that the defect levels dominating the gas-sensing performance but not the morphology, specific surface area or crystal size.

Cited by 61 publications

References 45 publications

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

Effect of annealing temperature on photoluminescence emission and photocatalytic activity of hydrothermal ZnO nanorods

New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method

Correlation between Microstructure and Chemical Composition of Zinc Oxide Gas Sensor Layers and Their Gas-Sensitive Properties in Chlorine Atmosphere

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Product

Resources

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C₂H₅OH and NO₂ sensing properties of ZnO nanostructures: correlation between crystal size, defect level and sensing performance

New Design of ZnO Nanorod- and Nanowire-Based NO₂ Room-Temperature Sensors Prepared by Hydrothermal Method