Rhodamine 6g Surface Enhanced Fluorescence Effects Of Self-assembly Of Silver Island Film

Surface enhanced fluorescence technology is a new field developed in recent years, which uses some special substrates to enhance fluorescence emission of the fluorophores adsorbed onto the substrates. The researchers dedicated to both theoretical and experimental research and achieved remarkable results since the 1990s. Based on fluorescence detection technology features high sensitivity, the researchers have this technology widely used in biomedical, single molecule detection and other areas of research. There are two important factors for the researches of SEF, such as substrate and fluorophore, especially, the selection of the substrate is very important. In a long period of time, people mainly observed the quenching phenomenon because of the limit of substrates, which once restricted the development of SEF. However, the rapid development of nano-materials in recent years provided abundant substrates for the tests and the technology of SEF blossomed again.In this paper, the surface enhanced fluorescence effects of Rh6G molecule have been investigated by using silver nanoparticles including the silver colloid, assembled structure of silver nanoparticles and annealing assembled structure of silver nanoparticles as substrates. This paper is divided into three parts:the first part studied the fluorescence enhancement effect of silver colloid substrate surface to Rh6G. The second part deals with surface enhanced fluorescence of Rhodamine 6G on assembled silver nanoparticles. The third part does with fluorescence enhancement of Rhodamine 6G from annealing silver island films.Part one:We used the silver colloid as the substrate and gained an emission enhancement of Rhodamine 6G solution. Experiment results show that there are important factors effect surface enhanced fluorescence, such as plasmon resonance of silver nanoparticles, the distance between the surface of silver colloid and Rh6G molecules.Part two:In this part, the fluorescence emission and enhancement of Rhodamine 6G on the silver island films (SiFs) with and without 4-Aminothiophenol molecules have been investigated. It was found that the SiFs without 4-Aminothiophenol molecules (PATP) have less contribution to the fluorescence enhancement. However, when PATP molecules as a spacer were deposited on the SiFs, obvious fluorescence enhanced effect was observed. The results show that the fluorescence enhancement depends on the morphology of the substrate surface and the distance between fluorophore molecules and the substrate surface. The experimental observations can be explained by local surface plasmon resonance and local field enhancement theory.Part there:Silver island films annealed in different temperatures were employed as enhancement surface. We successfully gained the surface enhanced fluorescence effects for Rh6G fluorophore with laser spectroscopic technique. We designed two different experimental ways, solid environment and liquid environment. Solid environment was brought about by soaking the substrates in Rh6G solution and then a final rinse with water and drying with N2. But there were some weak points in this method, such as baddly-distrubution and hardly to apply. So we make the liquid environment for modification, which were constructed with sandwiched configuration to keep the molecules in liquid phase. We got similar results in the two different constructions, which is strong fluorescence enhancements were observed for Rh6G at SiFs at annealing 400℃. The results also showed that the enhancement effect of Rh6G fluorescence strongly depended on the surface morphology of annealing silver island films substrates. The corresponding mechanism behind the experimental phenomena was discussed with Mie theory and local field enhancement theory.