Comparative study on gas sensing properties of rare earth (Tb, Dy and Er) doped ZnO sensor

Hastir, Anita; Kohli, Nipin; Singh, Ravi Chand

doi:10.1016/j.jpcs.2017.02.004

Cited by 161 publications

(47 citation statements)

References 43 publications

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“…For ZnO gas sensors, the intrinsic defects are the key points that dominate the type of adsorption/desorption and the amount of defects which participate in the chemical reactions would directly affect the sensitivity of gas sensors 35–37 . In order to promote the properties of ZnO-based gas sensors, the chemical configurations and the distribution of defects should be clearly realized.…”

Section: Resultsmentioning

confidence: 99%

Strong correlation between optical properties and mechanism in deficiency of normalized self-assembly ZnO nanorods

Chang

Brahma

Huang

et al. 2019

Sci Rep

104

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Although, post annealing is an efficient way to annihilate/restructure deficiencies in self-assembly (SA) ZnO nanorods (ZNRs), the detailed investigation about the surface properties of annealed SA-ZNRs is a long standing issue and the major discrepancy is mainly due to single step annealing. We demonstrate the strategic two step annealing process to create reliable structural configuration in SA-ZNRs during the first round of annealing at 800 °C in vacuum (VA process), and create intrinsic defects in the second step of annealing in oxygen rich atmosphere (OA process) to correlate the formation of the defects related to green/orange-red emission. SA-ZNRs annealed in VA-OA processes reveal positive correlations between the oxygen flow rate and formation of oxygen interstitials (Oi) and zinc vacancies (VZn). The OA-VA processes exhibit the relation of residual Oi and additional Vo. According to VA-OA and OA-VA processes, we propose that the green emission in ZnO annealed in oxygen poor/rich condition is mainly due to the formation of Vo/VZn and annealing at oxygen rich condition creates Oi that lead to strong orange-red emission. Rather than O1s, we propose a reliable method by considering the peak shift of Zn2p in XPS to inspect the ZnO matrix, which has good interdependence with the characteristics of PL.

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Section: Resultsmentioning

confidence: 99%

Strong correlation between optical properties and mechanism in deficiency of normalized self-assembly ZnO nanorods

Chang

Brahma

Huang

et al. 2019

Sci Rep

104

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“…1,12,13 , becomes very important for improving the optical and electrical properties. This is fascinating for gas sensing applications as well due to their fast oxygen ion mobility, effective catalytic nature, and high surface basicity of the RE-based materials 1, 14,15 . For instance, Xu and Yan fabricated a new fluorescent sensor based on Eu 3+functionalized ZnO at metal-organic frameworks for volatile aldehyde gases (acetaldehyde, acraldehyde and formaldehyde) detection in ppb range at room temperature 16 .…”

Section: Introductionmentioning

confidence: 99%

Pd-Functionalized ZnO:Eu Columnar Films for Room-Temperature Hydrogen Gas Sensing: A Combined Experimental and Computational Approach

Lupan

Khaledialidusti

Mishra

et al. 2020

ACS Appl. Mater. Interfaces

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Reducing the operating temperature to room temperature is a serious obstacle on long-life sensitivity with long-term stability performances of gas sensors based on semiconducting oxides and this should be overcome by new nano-technological approaches. In this work, we report the structural, morphological, chemical, optical and gas detection characteristics of Eu-doped ZnO (ZnO:Eu) columnar films as a function of Eu content. The scanning electron microscopy (SEM) investigations showed that columnar films, grown via synthesis from chemical solutions (SCS) approach, are composed of densely packed columnar type grains. The sample sets with a content of ~0.05, 0.1, 0.15 and 0.2 at% of Eu in ZnO:Eu columnar films were studied. The surface functionalization was achieved using PdCl2 aqueous solution with additional thermal annealing in air at 650 ºC. The temperature dependent gas-detection characteristics of Pd-functionalized ZnO:Eu columnar films were measured in detail, showing a good selectivity towards H2 gas at operating OPT temperatures of 200-300 ºC among several test gases and volatile organic compounds (VOCs) vapors; such as methane, ammonia, acetone, ethanol, n-butanol and 2propanol. At an operating temperature OPT of 250 ºC a high gas response Igas/Iair ~ 115 for 100 ppm H2 was obtained. Experimental results indicate that Eu-doping with an optimal content about 0.05-0.1 at% along with Pd-functionalization of ZnO columns leads to a reduction of the operating temperature of the H2 gas sensor. DFT based computations provide mechanistic insights into the gas sensing mechanism by investigating interactions between the Pd-functionalized ZnO:Eu surface and H2 gas molecules supporting the experimentally observed results. The proposed columnar materials and gas sensor structures would provide a special advantage in the fields of fundamental research, applied physics studies, ecological and industrial applications.

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“…Rare earth (RE) ions, especially lanthanide (Ln) ions, have particularly excellent luminescence characteristics with extremely sharp emission bands, making them attractive for use in technological applications, such as optoelectronics devices [1][2][3][4][5] and sensors [6,7]. These properties arise from their 4f-4f electronic transitions.…”

Section: Introductionmentioning

confidence: 99%

Tb3+/Eu3+ Complex-Doped Rigid Nanoparticles in Transparent Nanofibrous Membranes Exhibit High Quantum Yield Fluorescence

Lu¹,

Wang²,

Huang³

et al. 2020

Nanomaterials

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In this study, transparent membranes containing luminescent Tb3+ and Eu3+ complex-doped silica nanoparticles were prepared via electrospinning. We prepared the electrospun fibrous membranes containing Tb(acac)3phen- (acac = acetylacetone, phen = 1,10-phenanthroline) and/or Eu(tta)3phen- (tta = 2-thenoyltrifluoroacetone) doped silica (M-Si-Tb3+ and M-Si-Eu3+) and studied their photoluminescence properties. The fibrous membranes containing the rare earth complexes were prepared by electrospinning. The surface morphology and thermal properties of the fibrous membrane were studied by atomic force microscopy (AFM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Fluorescence spectroscopy was used to characterize the fluorescence properties of the membranes. During the electrospinning process, the PVDF transitions from the α phase to the β phase, which exhibits a more rigid structure. The introduction of rigid materials, like PVDF and silica, can improve the fluorescence properties of the hybrid materials by reducing the rate of nonradiative decay. So the emission spectra at 548 nm (Tb) and 612 nm (Eu) were enhanced, as compared to the emission from the pure complex. Furthermore, the fluorescence lifetimes ranged from 0.6 to 1.5 ms and the quantum yields ranged from 32% to 61%. The luminescent fibrous membranes have potential applications in the fields of display panels, innovative electronic and optoelectronic devices.

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Comparative study on gas sensing properties of rare earth (Tb, Dy and Er) doped ZnO sensor

Cited by 161 publications

References 43 publications

Strong correlation between optical properties and mechanism in deficiency of normalized self-assembly ZnO nanorods

Strong correlation between optical properties and mechanism in deficiency of normalized self-assembly ZnO nanorods

Pd-Functionalized ZnO:Eu Columnar Films for Room-Temperature Hydrogen Gas Sensing: A Combined Experimental and Computational Approach

Tb3+/Eu3+ Complex-Doped Rigid Nanoparticles in Transparent Nanofibrous Membranes Exhibit High Quantum Yield Fluorescence

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