Si- and Ge-mullite single crystals doped with foreign cations

掺杂外来阳离子的硅莫来石和锗莫来石单晶

• 批准号: 324324372
• 负责人: Professor Dr. Reinhard X. Fischer
• 金额: --
• 依托单位: Fachbereich 05: Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/324324372?language=en
• 关键词: Si; Ge; mullite; single; crystals

Intensive research on the properties of mullite was mainly performed on mullite powders and polycrystalline mullite ceramics within the last decades. Little work was documented on synthesis and characterization of mullite single crystals. There is no information on single crystals of mullites doped with rare-earth (RE) elements, although these materials display interesting luminescence properties as shown on corresponding powder materials. The first aim of this project is to study the incorporation mechanism of RE elements (Eu, Tb, Gd etc.) into the mullite structure and to determine their photo-luminescent properties with potential applications. For this aim RE-doped mullite single crystals (2:1 mullite, 2Al2O3 . SiO2) of centimeter size will be synthesized by the Czochralski method. They will be characterized by microchemical, spectroscopic and crystal-chemical methods. A second aim of the project focusses on the basic crystal-chemical study of the incorporation of RE elements combined with "lone-pair-elements" (Pb, Bi) in the germanium analog of mullite, 'germanium-mullite' (3 Al2O3 . 2GeO2). The synthesis will be performed in a series of flux experiments of RE-doped germanium mullites out of Pb- or Bi-containing high-temperature melts. This basic research study intends to shed light on the suggested complex and novel incorporation mechanism of foreign cations with lone electron pairs in the mullite crystal structure. For this purpose, for the first time large RE-doped Si-mullite crystals and doped single crystals of Ge-mullite are synthesized and fundamentally characterized. Finally, with respect to mullite in a general sense, the contributions may be of great importance for the development of mullite materials.

在过去的几十年中，对Mullite的性质的深入研究主要是对Mullite粉末和多晶Mullite陶瓷进行的。关于Mullite单晶的合成和表征，很少有工作记录。尽管这些材料显示出有趣的发光特性，但如相应的粉末材料所示。该项目的第一个目的是研究元素（欧盟，结核病，GD等）的掺入机制，并用潜在的应用确定其光发光特性。对于此目的，将通过Czochralski方法合成厘米尺寸的浓度的Mullite单晶（2：1 Mullite，2al2o3。Sio2）。它们的特征是微化学，光谱和晶体化学方法。该项目的第二个目的重点是将元素结合的基本晶体化学研究以及“孤级元素”（pb，bi）结合在mullite的锗类似物中的“ lone pb，bi），'仙女 - 毛利石'（3 Al2o3）中。 2GEO2）。该合成将在一系列的通量实验中进行，该实验是通过含PB或双含量的高温熔体的重掺杂的锗的植物。这项基础研究旨在阐明外国阳离子在穆尔特晶体结构中使用孤独电子对的复合和新颖的结合机理。为此，首次合成了大型重新掺杂的Si-rullite晶体和掺杂的Ge-rullite的掺杂的单晶，并从根本上进行了表征。最后，就一般意义上的穆利特而言，对于开发mullite材料而言，贡献可能非常重要。