Band gap engineering of transition metal (Ni/Co) codoped in zinc oxide (ZnO) nanoparticles

Ali, Rai Nauman; Naz, Hina; Li, Jing; Zhu, Xingqun; Liu, Ping; Xiang, Bin

doi:10.1016/j.jallcom.2018.02.072

Cited by 86 publications

(22 citation statements)

References 36 publications

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“…As E form of O i 2− decreases with a gradient of −2, a lower E form of O i 2− near the LUMO can be achieved by increasing the band-gap. This suggests that band-gap engineering by mixing the constituent elements with others with the same valences can increase the band-gap, as in previous studies on In x Ga 1− x N 29 , mixed anion lead halide perovskites 30 , and Ni- and Co-doped ZnO nanoparticles 31 . In the In x Ga 1− x N case, the LUMO increases as an increase of the Ga content because an energy level of Ga s is higher than that of In s , resulting in an increase of the band-gap.…”

Section: Resultssupporting

confidence: 70%

Oxygen conduction mechanism in Ca3Fe2Ge3O12 garnet-type oxide

Lee

Ohba

Asahi

2019

Sci Rep

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We investigate the oxygen conduction mechanism in a garnet-type oxide, Ca 3 Fe 2 Ge 3 O 12 , for the first time in detail by first-principle calculations. The nudged elastic band results confirm that this oxide has a lower migration barrier energy (0.45 eV) for an oxygen interstitial (O i ) with the kick-out mechanism than that (0.76 eV) for an oxygen vacancy. The migration paths for O i are delocalized and connected to the neighboring cells in three-dimensional space. This oxide does not have a very low formation energy of O i when the Fermi level is near the lowest unoccupied molecular orbital at a high temperature, which implies the possibility of electron doping by high-valence cations. These theoretical results suggest that the doping of Ca 3 Fe 2 Ge 3 O 12 for generation of excess O i provides a good oxygen-ion conductivity, along with the electronic conductivity.

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Section: Resultssupporting

confidence: 70%

Oxygen conduction mechanism in Ca3Fe2Ge3O12 garnet-type oxide

Lee

Ohba

Asahi

2019

Sci Rep

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“…The observed diffraction pattern revealed that the hexagonal form of host matrix was fairly well maintained irrespective of the incorporation of Co or Ni. Furthermore, no additional diffraction peaks associated to any phase of Ni, NiO, Co, or CoO or dopant traces except peaks from PET were detected in our XRD resolution limit [ 26 ]. This means that Co or Ni dopants did not produce any secondary compound phases during the NR growth but were fairly well dissolved as dopants into the host lattice matrix by replacing Zn sites.…”

Section: Resultsmentioning

confidence: 99%

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Ajmal¹,

Khan²,

Nam³

et al. 2020

Nanomaterials

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A growth scheme at a low processing temperature for high crystalline-quality of ZnO nanostructures can be a prime stepping stone for the future of various optoelectronic devices manufactured on transparent plastic substrates. In this study, ZnO nanorods (NRs) grown by the hydrothermal method at 150 °C through doping of transition metals (TMs), such as Co, Ni, or Co-plus-Ni, on polyethylene terephthalate substrates were investigated by various surface analysis methods. The TM dopants in ZnO NRs suppressed the density of various native defect-states as revealed by our photoluminescence and X-ray photoelectron spectroscopy analysis. Further investigation also showed the doping into ZnO NRs brought about a clear improvement in carrier mobility from 0.81 to 3.95 cm2/V-s as well as significant recovery in stoichiometric contents of oxygen. Ultra-violet photodetectors fabricated with Co-plus-Ni codoped NRs grown on an interdigitated electrode structure exhibited a high spectral response of ~137 A/W, on/off current ratio of ~135, and an improvement in transient response speed with rise-up and fall-down times of ~2.2 and ~3.1 s, respectively.

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“…The response of ZnO nanomaterials was improved in a similar way. The RGO enhanced the sensing response of ZnO towards VOCs, H 2, and NO 2 at 200−250 • C [7,85].…”

Section: Surface Photoactivationmentioning

confidence: 99%

“…Thanks to heterogeneous photocatalysis studies, it was discovered that many of the metal oxide materials have their principal optical and electronic transitions in the near-UV region of the electromagnetic spectrum (Eλ = 2.5-5 eV). For example, ZnO, Furthermore, it has recently been shown that the incorporation of 1D metal oxides with two-dimensional (2D) graphene oxide (GO) is a promising approach to fabricate composite structures with improved gas sensing performance [7,[83][84][85]. A composite structure based on TiO 2 nanotubes and reduced GO (RGO) was obtained (RGO-TiO 2 ) [84].…”

Section: Surface Photoactivationmentioning

confidence: 99%

Chemical Gas Sensors Studied at SENSOR Lab, Brescia (Italy): From Conventional to Energy-Efficient and Biocompatible Composite Structures

Galstyan

Kaur

Zappa

et al. 2020

Sensors

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In this paper, we present the investigations on metal oxide-based gas sensors considering the works performed at SENSOR lab, University of Brescia (Italy). We reported the developments in synthesis techniques for the preparation of doped and functionalized low-dimensional metal oxide materials. Furthermore, we discussed our achievements in the fabrication of heterostructures with unique functional features. In particular, we focused on the strategies to improve the sensing performance of metal oxides at relatively low operating temperatures. We presented our studies on surface photoactivation of sensing structures considering the application of biocompatible materials in the architecture of the functional devices as well.

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Band gap engineering of transition metal (Ni/Co) codoped in zinc oxide (ZnO) nanoparticles

Cited by 86 publications

References 36 publications

Oxygen conduction mechanism in Ca3Fe2Ge3O12 garnet-type oxide

Oxygen conduction mechanism in Ca3Fe2Ge3O12 garnet-type oxide

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Chemical Gas Sensors Studied at SENSOR Lab, Brescia (Italy): From Conventional to Energy-Efficient and Biocompatible Composite Structures

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