Highly defective MgO nanosheets from colloidal self-assembly

Optical and fluorescence properties of MgO nanoparticles in micellar solution of hydroxyethyl laurdimonium chloride

“…These defects are located on the different coordination sites on the surface and thus, undergo excitation when exposed to UV photon energy. It has been shown that the cubic-MgO is a wide-band gap energy material and normally does not demonstrate the fluorescence characteristic [13,25,7]. In the MgO crystalline structure, some structural defects are present, such as magnesium vacancies (3 and 4-coordinated Mg 2+ ) and oxygen vacancies (3 and 4-coordinated O 2− ) [10,26].…”

“…Indeed, a defected surface usually plays a decisive role in catalysis, reactivity, optical and transport properties at oxide surfaces [9,12]. Generally defects, such as point defects, F-centers and intrinsic/extrinsic defects which are created during various synthetic methods may form luminescent centers on the insulating surface of materials [13]. The application of a surfactant to solubilize MgO nanoparticles provides a means to achieve control over the MgO nanoparticle size and size distribution in solution, which is essential for tailoring optical, electrical, chemical, and magnetic properties of nanoparticles for specific applications.…”

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

“…36 An incomplete oxidation process during the transformation of Mg(OH) 2 into MgO NPs is responsible for oxygen vacancies on the surface, which may give PL emission. [36][37][38][39] The broad and asymmetric emission peak which is centred in the blue region of the spectrum with high intensity in the PL spectra of MgO NPs is assigned to the structural defects during synthesis. 40 Thus, the PL study conrms the presence of surface defects on the MgO NPs due to oxygen vacancies.…”

Defect and adsorbate induced ferromagnetic spin-order in magnesium oxide nanocrystallites

“…Moreover, recently, it has been realized that even prohibitive cation defects ($4.6% more than the thermodynamically allowed), suggested as percolation threshold for FM spin-order would not lead to FM. 10 The density functional theory (DFT) based calculations performed with local approximations of the exchange correlation potentials such as spin density approximation (LSDA) and the generalized gradient approximation (GGA) have themselves been criticized for their qualitative failures in description of hole centers in MgO. 18 Fig .…”

“…9 It was assumed that vacuum annealing results in creation of oxygen vacancies, which subsequently reduces magnetic moments and, therefore, the observed RTFM spin-order was perceived as induced by magnesium vacancies. Recently, Maoz et al 10,11 noticed that air annealing too reduced magnetic spin-order in MgO nano-sheets and suggested one electron trapped oxygen vacancies (F þ ) to cause the observed ferromagnetic spin-order. Very recently, Wang et al 12 exhibited invariable magnetic moments when annealing in air was performed below 1000 C. Further, Balcells et al 13 observed vacuum annealing of five months air exposed MgO thin films at 850 C to reveal enhanced magnetic moments.…”