Ag@Fe3O4@C-CdTe@SiO2磁性荧光复合微球的制备与光学特征

先采用一步溶剂热法和水热法制备了碳包覆的Ag@Fe₃O₄核壳型磁性纳米粒子，然后通过表面氨基化改性后与巯基乙酸修饰的CdTe量子点反应，将量子点键合到磁性微球上，最后在其表面包覆上一层二氧化硅壳层，制备出具有荧光增强的Ag@Fe₃O₄@C-CdTe@SiO₂磁性荧光复合材料。实验结果表明，该纳米粒子的平均粒径大约为150 nm，磁饱和强度为224 A/g（22.4 emu/g），在室温下具有较好的磁性能。其中Ag@Fe₃O₄@C-CdTe磁性荧光纳米粒子的荧光强度大于Fe₃O₄@C-CdTe，其主要原因是内核为45 nm的Ag纳米粒子具有表面等离子体共振作用，能够使其表面或附近的量子点荧光得到增强。

Magnetic and Optical Properties of Ag@Fe3O4@C-CdTe@SiO2 Hybrid Nanoparticles

Novel hybrid nanoparticles Ag@Fe3O4@C-CdTe@SiO2 were prepared.The synthesis method is included of a Fe3O4 magnetic embedded Ag core (Ag@Fe3O4),an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe3O4@C-PEI),the grafting of CdTe quantum dots (QDs) on the surface of Ag@Fe3O4@C-PEI (Ag@Fe3O4@C-CdTe),and an ordered SiO2 structured shell.The nanocomposites possess an average diameter of 150 nm,orange emission feature and the saturation magnetization of 224 A/g (22.4 emu/g),which has room temperature ferro-magnetism.The photoluminescence measurement reveals that the fluorescence of Ag@Fe3O4@C-CdTe nanostructures in this composite with the Ag cores of about 45 nm has more enhancement compared with that of Fe3O4@C-CdTe nanostructures due to the strong surface plasmonic resonance of the Ag cores.