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۱New Method for Synthesis of Zinc Metaborate Zn4B6O13 Crystals via Sol–Gel Process and Investigation of DFT Calculations
اطلاعات انتشار: International Journal Of Bio-Inorganic Hybrid Nanomaterials، اول،شماره۲، Summer۲۰۱۲، سال
تعداد صفحات: ۸
In this work facile sol–gel (pechni) method has been successfully established to synthesize Zn4B6O13 nanocrystals which have cubic crystals with lattice parameter: a =7.48 A. The structure and morphology of the obtained material were studied by X–ray diffraction (XRD), Infrared spectra (IR), scanning electron microscopy (SEM) and photoluminescence analysis. The experimental results show a band gap of 3.306 eV for the synthesized materials. Density functional theory (DFT) calculations by GGA–PBE method show, the crystals belong to the semiconductors with an indirect energy band gap of about 3.289 eV. The calculated band gap using the GGA–PBE method is comparable with the experimental results. The optical properties include the dielectric spectra; absorption, reflectivity and energy–loss spectra, and the origin of spectral peaks were analyzed based on the electronic structures.

۲Hydrothermal Synthesis, Characterization, Optical Properties Lithium Meta– and Disilicate Nanomaterials and Theoretical Calculations
اطلاعات انتشار: International Journal Of Bio-Inorganic Hybrid Nanomaterials، اول،شماره۳، Autumn۲۰۱۲، سال
تعداد صفحات: ۱۳
Highly crystalline and pure lithium metasilicate (Li2SiO3) and lithium disilicate (Li2Si2O5) nanomaterials were synthesized by hydrothermal method and characterized by PXRD technique.The changes in the morphology and particle size of the synthesized nanomaterials with reaction time were investigated using SEM technique. The UV–Vis and photoluminescence spectra of the compounds were studied. The intensity of the bands in the emission spectra increased with increasing reaction time in both compounds. The electronic band structure along with density of states (DOS) calculated by the DFT method that indicated Li2SiO3 and Li2Si2O5 had an indirect energy band gap of 4.575 eV and 4.776 eV, respectively. The optical properties, including the dielectric, absorption, reflectivity and energy–loss spectra of the compounds were calculated by DFT method and analyzed based on the electronic structures.
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