Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193, Aveiro, Portugal.
Department of Physics, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193, Aveiro, Portugal.
Chemistry. 2018 Aug 14;24(46):11926-11935. doi: 10.1002/chem.201802219. Epub 2018 Jul 25.
A new lanthanide silicate system, Na K[Ln Si O ] (Ln=Lu, Yb/ Er, Lu/Eu, or Lu/Yb/Er), comprising microcrystals embedded in an amorphous siliceous matrix, obtained by sintering at 1373 K a Na K[Ln Si O ]⋅3 H O nano-crystalline precursor, is reported. The crystal structure of these lanthanide silicates was solved from high-resolution synchrotron power X-ray diffraction data collected at 110 K, and further supported by Si MAS NMR and Eu luminescence. The materials crystallize in the Pī triclinic centrosymmetric space group, exhibiting a dense framework consisting of hexameric [Si O ] cyclosilicate units, and chains of two distinct {LnO } octahedra. Na K[(Lu Yb Er ) Si O ] is the first example of a lanthanide silicate operative as a near-infrared ratiometric luminescent thermometer, with good sensitivity at cryogenic temperatures (<100 K). Upon excitation at 903 nm, the ratio between the F → F (Yb ) and I → I (Er ) emissions was used for sensing temperature in the 12-450 K range, reaching a maximum thermal sensitivity of 2.6 % K at 26.8 K.
一种新的镧系硅酸盐体系，NaK[LnSiO]（Ln=Lu、Yb/Er、Lu/Eu 或 Lu/Yb/Er），由嵌入在无定形硅质基质中的微晶组成，通过在 1373K 下烧结 NaK[LnSiO]·3H2O 纳米晶前体制得。这些镧系硅酸盐的晶体结构是从在 110K 下收集的高分辨率同步加速器粉末 X 射线衍射数据中解出的，并进一步得到 29Si MAS NMR 和 Eu 发光的支持。这些材料在 Pī 单斜中心对称空间群中结晶，具有由六聚体[SiO]环己硅酸盐单元和两个不同的{LnO}八面体链组成的密集骨架。NaK[(LuYbEr)SiO]是作为近红外比率荧光温度计工作的镧系硅酸盐的第一个例子，在低温（<100K）下具有良好的灵敏度。在 903nm 激发下，使用 F→F（Yb）和 I→I（Er）发射的比率来感测 12-450K 范围内的温度，在 26.8K 时达到最大热灵敏度 2.6%K。
