距离调控纳米多孔金表面增强荧光特性

通过调控纳米多孔金(NPG)基底与荧光分子之间的距离,系统研究了其表面增强荧光特性.利用物理气相沉积方法在NPG表面沉积二氧化硅薄膜,通过调整二氧化硅的厚度来控制NPG与荧光分子之间的距离,系统研究了NPG孔径尺寸以及与荧光分子之间距离对其表面增强荧光(SEF)特性的影响.由于多孔金具有纳米级多孔结构,其表面等离子体能够通过分子附近局域电场的增强使分子的激发光场得到增强,从而提高分子的激发强度和效率;当荧光分子与多孔金表面存在一定距离时,通过与光子之间的共振耦合作用,表面等离子体能够增强多孔金周围电磁场,实现荧光增强.通过研究发现,NPG孔径为36nm、表面二氧化硅厚度为20nm时,表面组装的罗丹明6G荧光分子的荧光强度得到最大增强.

Distance Control Surface-enhanced Fluorescence Properties of Nanoporous Gold

The surface-enhanced fluorescence properties of nanoporous gold (NPG) films were investigated by controlling the distance between substrate and fluorescent molecules via silica depositing. Silica was coated on the surface of NPG by physical vapor deposition, and the distance between NPG surface and fluorescent molecules were determined by adjusting the thickness of the silica film. Both the nanopore size and the distance between substrate and fluorescent molecules affect the properties of surface-enhanced fluorescence. As nanoporous gold is of a nanometer porous structure, the surface plasmon of NPG can enhance the excitation field of a molecule by the enhancement of the local electric field near the molecule so as to enhance the excitation intensity and efficiency of the molecule. When there is an appropriate distance between the fluorescent molecule and the NPG surface, the surface plasmon can enhance the electromagnetic field around NPG through the resonance coupling with the photon, and achieve the fluorescence enhancement. It is found that the fluorescence from the assembled Rhodamine 6G molecules can achieve the best enhancement with 20 nm silica coated NPG films, and the optimal ligament size of NPG is 36 nm.