The Study Of Ag@SiO₂ Core-Shell Nanoparticles Enhancing Luminescence Of Rare Earth Comolexes

The paper has synthetized 10 kinds of rare earth complexes of Eu3+ and Tb3+, they take benzoic acid(BA), 3-amino pyrazine-2-carboxylic acid(ampca) and p-phthalic acid(PTA) as anionic ligands, and take 2,4,6-Tris(2-pyridy)-s-triazine(TPTZ) and 1,10-Phenanthroline monohydrate(phen) as netural ligands. We make sure the compositions of the rare earth complexes are RE(phen)(ampca)3·3H2O, RE(TPTZ)(BA)3·3H2O, RE(TPTZ)(ampca)3·3H2O, RE(phen)(BA)3·3H2O and RE(phen)(PTA)i.5·3H2O(RE= Eu3+、Tb3+) through elemental analysis, Uv-vis spectrum analysis and infrared spectrum analysis. Then we test the molar conductivity of the complexes, and the results of the test show that all of complexes are non-electrolyte. Finally, we test the fluorescent intensity of the complexes use the fluorescence spectrometer.Precious metals such as gold and silver have surface plasmon resonance effect, and many research results have showed that if we coat silica shell on the surface of metal nanoparticals, then make them reaction with rare earth complexes, the fluorescent intensity of rare earth complexes will be improved obviously. Therefore, in this paper, we have prepared seven kinds of Ag@SiO2 nanoparticals, they have different partical size and shell thickness. Then to study their influence on fluorescent intensity of rare earth complexes after making them reaction with the complexes. Among these particals, the shell thickness of the Ag@SiO2 nanoparticals whose partical size are in the range of 40nm and 60nm are 12nm,30nm and 40nm, and the shell thickness of the Ag@SiO2 nanoparticals whose partical size are in the range of 80nm and 100nm are 5nm,12nm,20nm and 30nm. The results of fluorescence test haved showed that the fluorescence intensity of the 10 kinds of rare earth complexes can be improved obviously under the action of Ag@SiO2 nanoparticals, and the highest ratio can reach to 21.40. What’s more, for the Ag@SiO2 nanoparticals with the same partical size and different shell thickness, within a certain range, the thicker of SiO2 shell, the larger of the ratio, but for the Ag@SiO2 nanoparticals with different partical size and the same shell thickness, the Ag@SiO2 nanoparticals whose partical size are in the range of 40nm and 60nm have the better enhancement effect than the Ag@SiO2 nanoparticals whose partical size are in the range of 80nm and 100nm.