کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1333574 979085 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electronic structure and photoluminescence properties of Eu2+-activated Ca2BN2F
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Electronic structure and photoluminescence properties of Eu2+-activated Ca2BN2F
چکیده انگلیسی

The electronic structure of undoped and luminescence properties of Eu2+-doped Ca2BN2F have been investigated. First-principles calculations for Ca2BN2F show that the valence band is mainly composed of F and N 2p, B 2s and 2p orbitals, while the Ca 4s and 3d are almost empty, indicating that Ca2BN2F is a very ionic compound. The valence band close to the Fermi level is dominated by the N 2p states, and the bottom of the conduction band is determined by the Ca 3d and N/B 3s orbitals. The direct energy gap is calculated to be about 3.1 eV, in fair agreement with the experimental data of ∼3.6 eV derived from the diffuse reflection spectrum. Due to the high degree of ionic bonding of the coordinations of Eu with (N, F) on the Ca sites, Ca2BN2F:Eu2+ shows strong blue emission with a maximum at about 420 nm upon UV excitation in the absorption range of 330–400 nm.

Diffuse reflection spectrum, excitation and emission spectra of Ca2BN2F:Eu2+, showing that only the ionic Eu2+ center offers deep blue emission at about 422 nm under excitation at 339 nm.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Solid State Chemistry - Volume 182, Issue 12, December 2009, Pages 3299–3304
نویسندگان
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