Band Gap Energies of Magnesium Oxide Nanomaterials Synthesized by the Sol-Gel Method

Badar, Nurhanna; Chayed, Nor Fadılah; Rusdi, Roshidah; Kamarudin, Norashikin; Kamarulzaman, Norlıda

doi:10.4028/www.scientific.net/amr.545.157

Cited by 45 publications

(21 citation statements)

References 13 publications

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“…Not much work have been presented in literature on the bandgaps of nanostructured MgO. The bandgaps of MgO nanoparticles are found to be between 5.40 to 6.2 eV [16][17][18][19][20] which is less than the bulk value of 7.8 eV. 21,22 However, these are not 2-D nanostructures.…”

mentioning

confidence: 95%

Band Gap Narrowing of 2-D Ultra-Thin MgO Graphene-Like Sheets

Kamarulzaman

Chayed

Badar

et al. 2016

ECS J. Solid State Sci. Technol.

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Ultra-thin MgO nanosheets obtained by a sol-gel method were found to have cubic crystal structure with a space group of Fm-3m. The thickness of the sheets for the 600°C and 5 h annealing condition sample is 2 nm. Although the MgO sheets are two-dimensional and ultra-thin, unlike graphene, they are polycrystalline. Their bandgap energies are dependent on the thermal annealing conditions (which affect the thickness of the MgO nanosheets). It is found that there was bandgap narrowing of the MgO nanosheets with respect to the bulk values. UV-visible spectroscopy and X-Ray Photoelectron spectroscopy (XPS) enables us to identify the shifts of the valence and conduction bands causing the bandgap narrowing.

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mentioning

confidence: 95%

Band Gap Narrowing of 2-D Ultra-Thin MgO Graphene-Like Sheets

Kamarulzaman

Chayed

Badar

et al. 2016

ECS J. Solid State Sci. Technol.

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“…The lowest transition situated at 3.6 eV corresponds to wurtzite phase. The second one approaches that of the MgO thin films, estimated by Badar et al at 5.5 eV [28]. The transmittance spectra recorded for the samples with columnar growth (for x = 0.6 or 0.8) exhibit larger amplitude fringes probably due to the diminution of surface roughness [26].…”

Section: Optical Propertiesmentioning

confidence: 79%

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Mahdjoub¹,

Hafid²,

Aida³

et al. 2017

Semicond. Phys. Quantum Electron. Optoelectron.

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Zn (1-x) Mg x O thin films with various concentrations of magnesium were deposited using the spray pyrolysis method. The transmittance spectra recorded for all films exhibit maxima exceeding 90%. The band gap energy of the films with wurtzite structure increases from 3.22 up to 3.60 eV by incorporating Mg into ZnO. However, when the atomic ratio of Mg exceeded 0.4, a second crystalline phase (assigned to cubic MgO) became discernable in XRD patterns, a compressive strain was observed in the wurtzite lattice, and crystallite sizes decreased significantly. In accordance with these observations, finer grains with a pronounced columnar growth were observed in 3D AFM representations and the surface roughness decreases significantly. Finally, selective etching in water yields to porous films with a great surface-to-volume ratio, a lower refractive index and a better light transmission. These porous films with tunable band gap seem to be excellent candidates to various interesting applications.

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“…Thus, it was expected that our MgO NPs presented absorption bands in the visible part of the spectrum because the occurrence of punctual defects was enhanced by the nanometric scale. Figure 6 presents the Tauc plot of the MgO NPs sample, where the intercepts are associated to photons of energies 6.15, 5.40, and 4.75 eV, which corresponds to oxygen low coordination sites associated with terraces ( − ), corners ( − ), and steps ( − ), respectively (see Figure 4a) [19,21,22,66,67,68,69,70]. Additionally, a MgO NP sample was irradiated by intense 365 nm UV light for 4 h; in this case, the UV-Vis absorption spectra also presented high absorption for wavelengths below 200 nm, but contrary to the NP sample kept in the dark, it only presented one intense absorption band at 226 nm (Figure 4).…”

Section: Mgo Nanoparticles Characterizationmentioning

confidence: 99%

“…presents the Tauc plot of the MgO NPs sample, where the intercepts are associated to photons of energies 6.15, 5.40, and 4.75 eV, which corresponds to oxygen low coordination sites associated with terraces (O 2− 5C ), corners (O 2− 4C ), and steps (O 2−3C ), respectively (seeFigure 6a)[19,21,22,[66][67][68][69][70].…”

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confidence: 99%

Two-Step Triethylamine-Based Synthesis of MgO Nanoparticles and Their Antibacterial Effect against Pathogenic Bacteria

et al. 2021

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Magnesium oxide nanoparticles (MgO NPs) were obtained by the calcination of precursor microparticles (PM) synthesized by a novel triethylamine-based precipitation method. Scanning electron microscopy (SEM) revealed a mean size of 120 nm for the MgO NPs. The results of the characterizations for MgO NPs support the suggestion that our material has the capacity to attack, and have an antibacterial effect against, Gram-negative and Gram-positive bacteria strains. The ability of the MgO NPs to produce reactive oxygen species (ROS), such as superoxide anion radicals (O2•-) or hydrogen peroxide (H2O2), was demonstrated by the corresponding quantitative assays. The MgO antibacterial activity was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, with minimum inhibitory concentrations (MICs) of 250 and 500 ppm on the microdilution assays, respectively. Structural changes in the bacteria, such as membrane collapse; surface changes, such as vesicular formation; and changes in the longitudinal and horizontal sizes, as well as the circumference, were observed using atomic force microscopy (AFM). The lipidic peroxidation of the bacterial membranes was quantified, and finally, a bactericidal mechanism for the MgO NPs was also proposed.

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Band Gap Energies of Magnesium Oxide Nanomaterials Synthesized by the Sol-Gel Method

Cited by 45 publications

References 13 publications

Band Gap Narrowing of 2-D Ultra-Thin MgO Graphene-Like Sheets

Band Gap Narrowing of 2-D Ultra-Thin MgO Graphene-Like Sheets

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Two-Step Triethylamine-Based Synthesis of MgO Nanoparticles and Their Antibacterial Effect against Pathogenic Bacteria

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