SrAlSi4N7:Eu2+ − A Nitridoalumosilicate Phosphor for Warm White Light (pc)LEDs with Edge-Sharing Tetrahedra

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• 作者：Cora Hecht ; Florian Stadler ; Peter J. Schmidt ; Jrn Schmedt auf der Gnne ; Verena Baumann ; Wolfgang Schnick
• 刊名：Chemistry of Materials
• 出版年：2009
• 出版时间：April 28, 2009
• 年：2009
• 卷：21
• 期：8
• 页码：1595-1601
• 全文大小：235K
• 年卷期：v.21,no.8(April 28, 2009)
• ISSN：1520-5002

文摘

The new nitridoalumosilicate phosphor SrAlSi₄N₇:Eu²⁺ has been synthesized under nitrogen atmosphere at temperatures up to 1630 °C in a radio-frequency furnace starting from Sr metal, α-Si₃N₄, AlN, and additional Eu metal. The crystal structure of the host compound SrAlSi₄N₇ has been solved and refined on the basis of single-crystal and powder X-ray diffraction data. In the solid, there is a network structure of corner-sharing SiN₄ tetrahedra incorporating infinite chains of all edge-sharing AlN₄ tetrahedra running along [001] (SrAlSi₄N₇: Pna2₁ (No. 33), Z = 8, a = 11.742(2) Å, b = 21.391(4) Å, c = 4.966(1) Å, V = 12.472(4) ų, 2739 reflections, 236 refined parameters, R1 = 0.0366). The Eu²⁺-doped compound SrAlSi₄N₇:Eu²⁺ shows typical broadband emission originating from dipole-allowed 4f⁶(⁷F_J)5d¹ → 4f⁷ (⁸S_7/2) transitions in the orange-red spectral region (λ_max = 632 nm for 2% Eu doping level, 450 nm excitation) with a spectral width of FWHM = 2955 (± 75) cm⁻¹ and a Stokes shift ΔS = 4823 (± 100) cm⁻¹. The luminescence properties make the phosphor an attractive candidate material as red component in trichromatic warm white light LEDs with excellent color rendition properties.