Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Inorg Chem. 2012 Mar 19;51(6):3540-7. doi: 10.1021/ic202340q. Epub 2012 Feb 29.
A novel oxonitridosilicate phosphor host Sr(3)Si(2)O(4)N(2) was synthesized in N(2)/H(2) (6%) atmosphere by solid state reaction at high temperature using SrCO(3), SiO(2), and Si(3)N(4) as starting materials. The crystal structure was determined by a Rietveld analysis on powder X-ray and neutron diffraction data. Sr(3)Si(2)O(4)N(2) crystallizes in cubic symmetry with space group Pa ̅3, Z = 24, and cell parameter a = 15.6593(1) Å. The structure of Sr(3)Si(2)O(4)N(2) is constructed by isolated and highly corrugated 12 rings which are composed of 12 vertex-sharing [SiO(2)N(2)] tetrahedra with bridging N and terminal O to form three-dimensional tunnels to accommodate the Sr(2+) ions. The calculated band structure shows that Sr(3)Si(2)O(4)N(2) is an indirect semiconductor with a band gap ≈ 2.84 eV, which is close to the experimental value ≈ 2.71 eV from linear extrapolation of the diffuse reflection spectrum. Sr(3-x)Si(2)O(4)N(2):xEu(2+) shows a typical emission band peaking at ~600 nm under 460 nm excitation, which perfectly matches the emission of blue InGaN light-emitting diodes. For Ce(3+)/Li(+)-codoped Sr(3)Si(2)O(4)N(2), one excitation band is in the UV range (280-350 nm) and the other in the UV blue range (380-420 nm), which matches emission of near-UV light-emitting diodes. Emission of Sr(3-2x)Si(2)O(4)N(2):xCe(3+),xLi(+) shows a asymmetric broad band peaking at ~520 nm. The long-wavelength excitation and emission of Eu(2+) and Ce(3+)/Li(+)-doped Sr(3)Si(2)O(4)N(2) make them attractive for applications in phosphor-converted white light-emitting diodes.
一种新型的氧氮硅酸盐荧光粉 Sr(3)Si(2)O(4)N(2) 通过高温固态反应在 N(2)/H(2)(6%)气氛下合成，使用的起始材料为 SrCO(3)、SiO(2)和 Si(3)N(4)。通过粉末 X 射线和中子衍射数据的 Rietveld 分析确定了晶体结构。Sr(3)Si(2)O(4)N(2) 呈立方对称，空间群为 Pa ̅3，Z = 24，晶胞参数为 a = 15.6593(1)Å。Sr(3)Si(2)O(4)N(2) 的结构由孤立的、高度扭曲的 12 元环组成，这些环由 12 个顶点共享的[SiO(2)N(2)]四面体组成，通过桥接的 N 和末端的 O 形成三维隧道，以容纳 Sr(2+)离子。计算得到的能带结构表明，Sr(3)Si(2)O(4)N(2) 是一种间接半导体，带隙约为 2.84eV，这与从漫反射光谱线性外推得到的实验值约 2.71eV 非常接近。Sr(3-x)Si(2)O(4)N(2):xEu(2+) 在 460nm 激发下表现出典型的发射峰在600nm 处，这与蓝色 InGaN 发光二极管的发射完全匹配。对于 Ce(3+)/Li(+)-共掺杂的 Sr(3)Si(2)O(4)N(2)，一个激发带在 UV 区(280-350nm)，另一个在 UV 蓝光区(380-420nm)，这与近 UV 发光二极管的发射匹配。Sr(3-2x)Si(2)O(4)N(2):xCe(3+),xLi(+) 的发射呈现出不对称的宽峰，峰值在520nm 左右。Eu(2+)和 Ce(3+)/Li(+)-掺杂 Sr(3)Si(2)O(4)N(2)的长波长激发和发射使它们成为在磷光体转换白光发光二极管中的应用有吸引力。
