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

Abstract

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.

Comparative Study of Conventional Electrolytes for Rechargeable Magnesium Batteries

“…On the other hand, inorganic species can be identified from the spectra of other elements, these include MgO/MgF 2 , Mg(OH) 2 , and MgCO 3 /MgCl 2 at 50.9 eV, [28b,29] 51.5 eV, [13b,29b,30] and 52.7 eV, respectively. The broad signal in low binding energy of Mg 2p spectra (49 eV) is assigned to Mg‐dangling bond [31] . The O 1s spectrum confirms the observation of MgO (529.1 eV [28b] ), Mg(OH) 2 /MgCO 3 (530.9 eV), [29a,b,32] and C−O (532.6 eV [28b] ).…”

“…The broad signal in low binding energy of Mg 2p spectra (49 eV) is assigned to Mgdangling bond. [31] The O 1s spectrum confirms the observation of MgO (529.1 eV [28b] ), Mg(OH) 2 /MgCO 3 (530.9 eV), [29a,b,32] and CÀ O (532.6 eV [28b] ). It should be noted that the B 1s spectra in all samples show no clear signal of boron containing species, which is probably due to low concentration of TBABH 4 in electrolyte solutions (Figure S10A).…”

Using a Chloride-Free Magnesium Battery Electrolyte to Form a Robust Anode–Electrolyte Nanointerface

“…49 A broad signal at 48.2−48.6 eV is assigned to Mg dangling bonds on the magnesium oxide surface. 51 The O 1s spectrum further corroborates the existence of MgO (529.6 eV) 47 and Mg(OH) 2 /MgCO 3 (533.6 eV). 48,49,52−54 The O 1s peak at 531.4 eV is assigned to the existence of oxygen vacancy in the MgO lattice.…”

“…At the top surface, the Mg 2p spectrum indicates the existence of Mg metal (49.8 eV), − MgO (51.0 eV), − and MgCO 3 and/or Mg­(OH) 2 (51.8 eV) . A broad signal at 48.2–48.6 eV is assigned to Mg dangling bonds on the magnesium oxide surface . The O 1s spectrum further corroborates the existence of MgO (529.6 eV) and Mg­(OH) 2 /MgCO 3 (533.6 eV). ,,− The O 1s peak at 531.4 eV is assigned to the existence of oxygen vacancy in the MgO lattice. − The O 1s spectrum also confirms the presence of organic species indicated by a strong peak at 532.8 eV, corresponding to C–O and/or CO containing species .…”

First-Principles investigation of the thermal properties of the XO (X = Be, Mg and Sr) nanosheet

“…Experimentally, a thin BeO layer has been synthesized using in-situ analytical techniques [20], and the 2D layered BeO structure was recently produced on silver layer via molecular epitaxial growth [21]. In experiments, fabricated materials are made using a variety of techniques, and MgO nanosheets are synthesized utilizing techniques such epitaxial growth phase of magnesium oxide (MgO) layers by pulsed laser deposition [22], MgO nanosheets were produced using a synthetic sol-gel technique [23][24][25], the heat and pressure formulation of methanol and ethanol with a brown coal y ash waste results in the production of , and chemical vapor deposition is used in a hydrothermal method procedure to create MgO nanosheets [29,30].…”