Study of active surface defects in Ti doped ZnO nanoparticles

Naeem, Muhammad; Qaseem, S.; Gul, Iftikhar Hussain; Maqsood, Adnan

doi:10.1063/1.3432571

Cited by 51 publications

(14 citation statements)

References 33 publications

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“…4b). This particle size-dependent shift in the optical band gap is found to be consistent with the literature [22]. We also conducted a detailed study on the role of particle size and concentration for the antibacterial activity of ZnO nanoparticles against Staphylococcus aureus.…”

Section: Resultssupporting

confidence: 89%

Size-dependent inhibition of bacterial growth by chemically engineered spherical ZnO nanoparticles

et al. 2019

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The antibacterial effect of ZnO nanoparticles is tested against Staphylococcus aureus, (a Grampositive pathogenic bacterium) from a particle-size, concentration, and surface-defects point of view. Activation of antibacterial activity was achieved by standard well diffusion agar and minimum inhibitory concentration procedures. Our results show that smaller-sized particles are more effective inhibitors of bacterial activity when used in a certain optimum concentration. To reveal the underlying mechanism of the observed size and concentration-dependent bacterial activity inhibition, we measured the concentrations of Zn 2+ ions released in each suspension by an inductive couple plasma optical emission spectrophotometer. Additionally, photoluminance spectra of our samples show significant surface defects (mainly oxygen vacancies) that generate reactive oxygen species. The underlying mechanism of the observed size-and concentration-dependent bacterial activity inhibition is attributed primarily to the release of Zn 2+ ions and generation of reactive oxygen species that interact and penetrate the cell membrane, causing lethal damage to the cell. Finally, the antibacterial effectiveness and maximum sensitivity of our nanoparticles is confirmed by optical density measurements. Keywords Zinc oxide. Reactive oxygen species ROS. Zn 2+ ion release. Antibacterial activity mechanism. Nanoparticles

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Section: Resultssupporting

confidence: 89%

Size-dependent inhibition of bacterial growth by chemically engineered spherical ZnO nanoparticles

et al. 2019

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“…It has been found that the intensity of DLE increases (Figure d) with increasing inclusion of Ti in the ZnO thin film up to 1%, since DLE depends on the density of free carriers and defects generated by the oxygen vacancies in the ZnO lattice. Here, the inclusion of Ti impurities could be the cause of the increase in the green light (at ∼560 nm) peak intensity, as reported by Chang et al As reported by Naeem et al, Ti impurities in the TZO-1 sample can increase the intensity of the green emission peak and increase the ionized oxygen vacancy in the ZnO lattice. However, at the high Ti doping concentration (TZO-3 and TZO-5), the PL intensity is observed to be slightly low compared to the TZO-1 sample, which may be ascribed to the increment in O i or Zn i defects.…”

Section: Resultssupporting

confidence: 57%

Quick NO Gas Sensing by Ti-Doped Flower–Rod-like ZnO Structures Synthesized by the SILAR Method

Soltabayev

Yergaliuly

Ajjaq

et al. 2022

ACS Appl. Mater. Interfaces

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In this study, Ti-doped ZnO films with flower−rod-like nanostructures were synthesized by the successive ionic layer adsorption and reaction (SILAR) method for enhanced NO gas-sensing applications. The stoichiometric ratio of Ti in the host ZnO lattice was confirmed by atomic absorption and energy-dispersive X-ray spectroscopies. All of the synthesized films exhibited a pure wurtzite hexagonal structure that seemed to deteriorate at high Ti doping contents as was manifested by the measured X-ray diffraction patterns. Scanning electron microscopy images of ZnO revealed the coexistence of porous flower-and rod-like structures, which became finer, denser, and more compact with Ti doping. By UV−vis measurements, the transmittance of the synthesized pure ZnO thin film in the visible region (∼75%) increased by about 10% with Ti doping, and the energy band gap seemed to decrease up to some limit of Ti content. Among the fabricated sensors (based on pure ZnO, 1% Ti-doped, 3% Ti-doped, and 5% Ti-doped ZnO films), the best sensing performance was observed for the 1% Ti-doped ZnO film. At first, this was associated with its high density of oxygen vacancies present on the surface of the film and ionized oxygen vacancies present in the ZnO lattice (confirmed, respectively, by X-ray photoelectron and photoluminescence spectroscopies). Nonetheless, this may also be due to its increased crystallinity (confirmed by X-ray diffraction and photoluminescence spectroscopy), high area-to-volume ratio (confirmed by scanning electron microscopy images), high specific surface area (confirmed by Brunauer−Emmett−Teller measurements) as well as high mobility and carrier concentration (confirmed by Hall measurements). The sensor was highly selective to NO gas and showed notable stability as well as very short response and recovery times, which makes it eligible for the early detection of any indoor or outdoor NO gas leakages.

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“…All the PL spectra have two emitting bands including a weak emission band in UV region (365 nm) and a strong emission band in visible region (centered at 550 nm). The UV emission band originates from the direct recombination of the free excitons through an exciton-exciton collision process, while the green emission peaks are due to radial recombination of the photo-generated hole with the electrons that belongs to the singly ionized oxygen vacancies [43][44][45]. When the ZnO:Co nanorods are annealed at different temperatures in the presence of O 2 , oxygen vacancy at the surface of ZnO is removed which results in the decrease of green emission.…”

Section: Gas Response and I-v Properties Of Zno:co Nanorodsmentioning

confidence: 98%

Synthesis and oxygen vacancy related NO2 gas sensing properties of ZnO:Co nanorods arrays gown by a hydrothermal method

Zou

Liang

Xue

2015

Applied Surface Science

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Study of active surface defects in Ti doped ZnO nanoparticles

Abstract: The effects of surface defect (oxygen vacancies) on the electronic structure and photoluminance

Cited by 51 publications

References 33 publications

Size-dependent inhibition of bacterial growth by chemically engineered spherical ZnO nanoparticles

Size-dependent inhibition of bacterial growth by chemically engineered spherical ZnO nanoparticles

Quick NO Gas Sensing by Ti-Doped Flower–Rod-like ZnO Structures Synthesized by the SILAR Method

Synthesis and oxygen vacancy related NO2 gas sensing properties of ZnO:Co nanorods arrays gown by a hydrothermal method

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