Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, PR China.
Langmuir. 2010 Jun 1;26(11):8850-6. doi: 10.1021/la904596x.
Mesoporous silica encapsulating upconversion luminescence NaYF(4) nanorods with uniform core-shell structures have been successfully synthesized by the surfactant-assistant sol-gel process. The thickness of ordered mesoporous silica shells can be adjusted from 50 to 95 nm by varying the amount of hydrolyzed silicate oligomer precursors from tetraethyl orthosilicate (TEOS), which further influences the BET surface area, pore volume, and the luminescence intensity. After coated with mesoporous silica shells, the hydrophobic nanorods is rendered to hydropholic simultaneously. The obtained beta-NaYF(4)@SiO(2)@mSiO(2) core-shell nanorods possess high surface area (71.2-196 m(2) g(-1)), pore volume (0.07-0.17 cm(3) g(-1)), uniform pore size distribution (2.3 nm), and accessible channels. Furthermore, the uniform core-shell nanorods show strong upconversion luminescence property similar to the hexagonal upconversion cores. The open mesopores can not only provide convenient transmission channels but also offer the huge location for accommodation of large molecules, such as fluorescent dyes and quantum dots. The secondary-excitation fluorescence of Rhodamine B is generated from the upconversion rare-earth fluoride nanorods cores to the fluorescent dyes loaded in the mesoporous silica shells.
具有均匀核壳结构的介孔硅封装上转换发光 NaYF(4) 纳米棒已通过表面活性剂辅助溶胶-凝胶法成功合成。通过改变正硅酸乙酯（TEOS）水解硅氧烷低聚物前体的量，可以将有序介孔硅壳的厚度从 50nm 调节到 95nm，这进一步影响了 BET 比表面积、孔体积和发光强度。介孔硅壳包覆后，疏水性纳米棒同时变为亲水性。所得到的β-NaYF(4)@SiO(2)@mSiO(2)核壳纳米棒具有高比表面积（71.2-196m(2) g(-1)）、孔体积（0.07-0.17cm(3) g(-1)）、均匀的孔径分布（2.3nm）和可及通道。此外，均匀的核壳纳米棒表现出类似于六方上转换核的强上转换发光性能。开放的介孔不仅提供了方便的传输通道，而且为大分子（如荧光染料和量子点）提供了巨大的容纳位置。罗丹明 B 的二次激发荧光是从上转换稀土氟化物纳米棒核到负载在介孔硅壳中的荧光染料产生的。
