Ba3Ga3N5鈥擜 Novel Host Lattice for Eu2+-Doped Luminescent Materials with Unexpected Nitridogallate Substructure

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• 作者：Frauke Hintze ; Franziska Hummel ; Peter J. Schmidt ; Detlef Wiechert ; Wolfgang Schnick
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：January 24, 2012
• 年：2012
• 卷：24
• 期：2
• 页码：402-407
• 全文大小：328K
• 年卷期：v.24,no.2(January 24, 2012)
• ISSN：1520-5002

文摘

The alkaline earth nitridogallate Ba₃Ga₃N₅ was synthesized from the elements in a sodium flux at 760 掳C utilizing weld shut tantalum ampules. The crystal structure was solved and refined on the basis of single-crystal X-ray diffraction data. Ba₃Ga₃N₅ (space group C2/c (No. 15), a = 16.801(3), b = 8.3301(2), c = 11.623(2) 脜, 尾 = 109.92(3)掳, Z = 8) contains a hitherto unknown structural motif in nitridogallates, namely, infinite strands made up of GaN₄ tetrahedra, each sharing two edges and at least one corner with neighboring GaN₄ units. There are three Ba²⁺ sites with coordination numbers six or eight, respectively, and one Ba²⁺ position exhibiting a low coordination number 4 corresponding to a distorted tetrahedron. Eu²⁺-doped samples show red luminescence when excited by UV irradiation at room temperature. Luminescence investigations revealed a maximum emission intensity at 638 nm (FWHM =2123 cm^鈥?). Ba₃Ga₃N₅ is the first nitridogallate for which parity allowed broadband emission due to Eu²⁺-doping has been found. The electronic structure of both Ba₃Ga₃N₅ as well as isoelectronic but not isostructural Sr₃Ga₃N₅ was investigated by DFT methods. The calculations revealed a band gap of 1.53 eV for Sr₃Ga₃N₅ and 1.46 eV for Ba₃Ga₃N₅.

Keywords:

nitridogallate; Eu²⁺-luminescence; DFT calculations; structure elucidation; band gap