纳米银对表面吸附镝配合物的荧光增强效应研究

研究了不同粒径的纳米银对镝配合物(乙二胺四乙酸配合物)的光谱学性质影响。当配合物溶液的pH值范围为4.0～6.0时，加入纳米银，可观察到大量的纳米银聚集体形成，而在吸收光谱的长波处出现一个新的吸收峰，随着纳米银浓度的增加，该吸收峰逐渐红移，同时，镝配合物的荧光强度增强。实验结果表明，纳米银粒子对镝配合物的荧光增强效应及荧光增强因子与纳米银粒子的浓度和粒径密切相关。随着纳米银浓度的增加，配合物的荧光强度先增强而后又逐渐降低。小粒径的纳米银对镝配合物的荧光增强因子较小。本文从纳米银粒子的聚集效应、局部电磁场增强效应及光吸收效应等方面探讨了纳米银对表面吸附镝配合物的+荧光增强效应机理。

Fluorescence Enhancement of Dysprosium Complex by Binding to Silver Nanoparticles

The photoluminescent properties of dysprosium complex (ethylenediamine tetra acetate) were investigated in the presence of different sized Ag nanoparticles. The formation of nanoparticles aggregates and a new absorption band at longer wavelength region were observed upon the addition of Ag nanoparticles when the pH value of the complex solution was 4.0～6.0. With the increase of the concentration of Ag nanoparticles, the peak at long wavelength was red-shifted, at the same time, enhancement of the emission intensity for the complex solution containing Ag nanoparticles was observed. The enhanced fluorescence of the complex and the enhancement factors were dependent on the concentration and size of Ag nanoparticles. With increasing Ag nanoparticles concentration enhancement factor first increases and then decreases. The enhancement factor of small Ag nanoparticles is lower than that of large Ag nanoparticles, meanwhile, the enhancement factor of small Ag nanoparticles can reach the maximum in lower Ag amount condition. The enhancement effect was discussed in terms of the effects of nanoparticle aggregates, the local electromagnetic field enhancement effect and optical absorption due to surface plasmon resonance.