Structural and Chemical Characterization of Aligned Crystalline Nanoporous MgO Films Grown via Reactive Ballistic Deposition

Dohnálek, Zdenek; Kimmel, Greg A.; McCready, David E.; Young, James A.; Dohnálková, Alice; Smith, R. Scott; Kay, Bruce D.

doi:10.1021/jp013801c

Cited by 95 publications

(145 citation statements)

References 22 publications

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“…16 They have active chemical sites with high binding energies, and are attractive candidates for application as sensors and heterogeneous catalysts. 17 More interestingly, the presence of oxygen vacancies in MgO NPs has a tremendous inuence on their electronic and chemical properties.…”

Section: -6mentioning

confidence: 99%

Preparation and characterization of MgO nanoparticles/ferroelectric liquid crystal composites for faster display devices with improved contrast

et al. 2014

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aIn this article, we present the formulation and characterization of a ferroelectric liquid crystal (FLC) mixture W301 composed of pyrimidine compounds. We observed that upon doping magnesium oxide nanoparticles (MgO NPs) into the host FLC, the MgO NPs/FLC composite showed significantly faster response and improved optical tilt angle. The decreased response time in the MgO NPs/FLC composite has been attributed to the decrease in rotational viscosity and increase in surface anchoring energy. The decrease in rotational viscosity of the composite is due to the torque experienced by both MgO NPs and FLC in the presence of an electric field and perturbations of order parameters of FLC. Due to the enhanced surface interaction of MgO NPs having surface defects with mesogens, strong surface anchoring is experienced on the FLC molecules that not only increased the speed of the response but also improved the optical tilt angle of the MgO NPs/FLC composites, which ultimately resulted in improved contrast. A systematic approach has been followed to elucidate the idea of designing faster display devices with improved contrast based on MgO NPs/FLC composites.

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Section: -6mentioning

confidence: 99%

Preparation and characterization of MgO nanoparticles/ferroelectric liquid crystal composites for faster display devices with improved contrast

et al. 2014

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“…Furthermore, the availability of various production techniques [6][7][8][9][10] has provided the basis for morphology-dependent trends in the abundance of specific surface features [11][12][13]. Paramagnetic superoxide O À 2 and ozonide O À 3 ions have been extensively investigated by Electron Paramagnetic Resonance (EPR) spectroscopy in the past [14][15][16] and a detailed review about the chemistry and paramagnetic properties of O À 3 species is given in Ref [14].…”

Section: Introductionmentioning

confidence: 99%

Ozonide ions on the surface of MgO nanocrystals

et al. 2007

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The adsorption properties of oxygen radicals on the surface of polycrystalline oxides can provide relevant information about the functionality of specific surface sites in oxidation catalysis. Using electron paramagnetic resonance spectroscopy, we investigated O 2 adsorption at MgO nanocrystal surfaces which were previously enriched with O ) radicals i.e. trapped hole centers. On dehydroxylated particle surfaces, two ozonide radical types O À 3 were isolated as adsorbates and the related energies for O 2 adsorption were found to be 55 ± 5 kJ mol )1 and 100 ± 5 kJ mol )1 . The respective adsorption sites are assigned to hole centers trapped on oxygen terminated corners and cation vancancies, respectively. In addition, O À 3 ions were also employed as probes for electron trapping sites on partially hydroxylated sample surfaces. Five types of O ) radicals emerge from surface colour centre bleaching with N 2 O, but only two of them adsorb O 2 at room temperature. A connection between the well-characterized (H + )(e -) defect -an electron trapped in close vicinity of a nearby proton [Chiesa et al. J. Phys. Chem. B 109 (2005) 7314] -and one ozonide type which exhibits significant magnetic coupling with an adjacent proton, was established on the basis of their production parameter dependence. Although the g tensor of an O 3 ) species reflects the properties of the radical itself rather than the structure of the adsorption site, the related signatures are proposed to serve also as spectroscopic fingerprints for catalytically relevant surface anion environments.

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“…[5][6][7][8] For the efficient investigation of surface sites, nanocrystalline model systems (where the number of surface ions is of the same order of magnitude as the number of bulk ions) are required. [9][10][11] Herein we report the production of nanometer-sized MgO nanoparticles by chemical vapor deposition (CVD). They attain an almost perfect cubic shape after thermal activation at 1170 K under high-vacuum conditions (p < 5 10 À6 mbar).…”

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confidence: 99%