纳米银对铕-吡啶-2,6-二羧酸配合物荧光增强效应的研究

摘要

The enhanced fluorescence effect of silver nanoparticles on a europium complex, Eu(III)DPA, where DPA is dipicolinic acid (C7H5NO4), with deionized (DI) water, heavy water, ethanol, and dimethylformamide as solvents, was studied. The results indicated that with increasing silver nanoparticle concentration, the intensities of the electric dipole transition (5D0→7F2)and magnetic dipole transition (5D0→7F1) first increased and then decreased, and the enhancement efficiency of 5D0→7F2 was higher than that of 5D0→7F1. The enhanced fluorescence effect of silver nanoparticles on Eu(III)DPA was maximum in ethanol. In the DI water, heavy water, and ethanol solution systems, the asymmetric ratio increased significantly, but there was little change in the dimethylformamide solution system. The observed silver nanoparticle dependence of the luminescent intensity of Eu(III)DPA was considered to be the result of stronger coupling between the surface plasmon resonance and the excited luminescence centers, and reabsorption of the surface plasmon resonance of silver nanoparticles.%研究了纳米银对分别以水、重水、乙醇和二甲基甲酰胺为溶剂的铕-吡啶-2,6-二羧酸(Eu(III)DPA)配合物溶液的荧光增强效应。研究结果表明, Eu(III)DPA溶液中加入纳米银,电偶极跃迁(5D0→7F2)和磁偶极跃迁(5D0→7F1)发射强度先增强而后逐渐下降,5D0→7F2的荧光增强效率高于5D0→7F1的荧光增强效率。在乙醇溶剂中纳米银对Eu(III)DPA溶液的荧光增强效应最大。在水或重水或乙醇溶剂中, Eu(III)DPA的不对称率明显提高,而在二甲基甲酰胺溶剂中几乎不变。分析认为,纳米银对Eu(III)DPA溶液荧光的影响与纳米银表面等离子体共振与激发态荧光中心强烈耦合以及表面等离子体再吸收有关。