Group (III) Nitrides M[Mg2Al2N4] (M = Ca, Sr, Ba, Eu) and Ba[Mg2Ga2N4]鈥擲tructural Relation and Nontypical Luminescence P

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• 作者：Philipp Pust ; Frauke Hintze ; Cora Hecht ; Volker Weiler ; Andreas Locher ; Daniela Zitnanska ; Sascha Harm ; Detlef Wiechert ; Peter J. Schmidt ; Wolfgang Schnick
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：26
• 期：21
• 页码：6113-6119
• 全文大小：449K
• ISSN：1520-5002

文摘

The isotypic nitridomagnesoaluminates M[Mg₂Al₂N₄] (M = Ca,Sr, Ba,Eu) as well as a novel nitridomagnesogallate Ba[Mg₂Ga₂N₄] have been synthesized by high-temperature reactions in arc-welded tantalum ampules. The crystal structures were solved and refined using single-crystal X-ray diffraction or powder X-ray diffraction data, respectively. All compounds crystallize in the UCr₄C₄-structure type (space group I4/m (no. 87), Z = 2, Ca[Mg₂Al₂N₄]: a = 8.0655(11), c = 3.2857(7) 脜, wR2 = 0.085 Sr[Mg₂Al₂N₄]: a = 8.1008(11), c = 3.3269(7) 脜, wR2 = 0.084; Eu[Mg₂Al₂N₄]: a = 8.1539(12), c = 3.3430(7) 脜, wR2 = 0.033; Ba[Mg₂Al₂N₄]: a = 8.2602(9), c = 3.43198(19) 脜, wRp = 0.031; Ba[Mg₂Ga₂N₄]: a = 8.3654(12), c = 3.4411(7) 脜, wR2 = 0.031) forming highly condensed anionic networks of disordered (Al/Mg)N₄ and (Ga/Mg)N₄ units, connected to each other by common edges and corners. The M²⁺ site is centered in vierer ring channels along [001] and coordinated in a cuboidal surrounding by N. Eu²⁺ doped samples of M[Mg₂Al₂N₄] (M = Ca,Sr,Ba) exhibit nontypical luminescence properties including trapped exciton emission in the red spectral region. These compounds widen the group of novel red-emitting materials such as Ca[LiAl₃N₄]:Eu²⁺, Sr[LiAl₃N₄]:Eu²⁺, or Sr[Mg₃SiN₄]:Eu²⁺. Therefore, deep discussion of the observed anomalous luminescence is essential to understand the correlations between all these materials, which are fundamental to design narrow band luminescence of Eu²⁺ systems.