The Porous Array Modulation Of Noble Metal Nanoparticles Assembled Structure Of Surface-enhanced Fluorescence Effect

In the suitable conditions, nanostructure metal substrates with a excitation of the incident light electric field, close to the substrate surface fluorescence molecular radiation behavior will become more stronger, these phenomenon called surface enhanced fluorescence effect. As one of the three branch of surface enhancement spectroscopy(SES), Surface enhanced fluorescence has been widely attention of the scholars because of its high sensitivity, better selectivity, and broadly application and so on. With the development of nanotechnology, the researchers already use various technically prepare different size, morphology and properties fluorescence enhancement substrates, the theory research as support its development, now local electromagnetic (EM) field enhancement, surface plasmon coupled emission (SPCE), and fluorescence resonance energy transfer (RET) are three the most representative theoretical model, the key all of this three theoretical model is effectively excite surface plasmons. With the excitation of the incident light electric field, the mental substrates which have suitable nanostructure will produce surface plasmons, which changes the distribution of local electromagnetic field near the metal substrate, improve the excitation efficiency of the fluorescence moleculer. Fluorescence detection technology as a high sensitivity detection means is development based on the SEF theory, it is widely used in biological diagnosis, genetic engineering and environmental testing and so on.In the study of surface enhanced fluorescence effect, the preparation and selection of the substrate is very important. Recently make use of sol-gel method to prepare gold or silver metal colloid already obtained very stable fluorescence enhancement effection. Make use of magnetron sputtering, evaporation, vacuum vapor deposition, laser etching to prepare continuous or not continuous metal films also caused most interesting of the scholar. With the deepening of the research theory and development of experiment technology, template synthesis method, which can control the size and shape of the nano-materials, becomes an important method for nano-materials. Through the the template synthesis prepare nano-wire, nano-dots, nano-tubes and nano-fragments were used for study of surface enhanced Raman scattering(SERS),but not very common in SEF. This paper combined with the advantages of porous anodic aluminum oxide (AAO) have nanoscale parallel arrays channel, which pore size, hole density and hole depth through changing the preparation conditions conveniently control and precious metal have good electromagnetic response, use self-assembly technology prepared precious metal nanoparticles modulated with porous array, study the fluorescence enhancement effection of the Rhodamine6G. The first part:The preparation and research of porous anodic alumina filmTwo-step anodic oxidation method is used to prepare highly ordered and hexagonal cellular structure AAO templates. Using atomic force microscope (AFM) and scanning electron microscope (SEM) analyzes the size and the morphology of the AAO. According to the experimental results, analyzes and discussing the influence on AAO pore and quality of film which caused by the voltage, current, temperature. Study the luminescent properties of AAO to Rh6G, the result demonstrated that the fluorescence enhancement of the Rh6G on the AAO substrate was5times higher than which on the glass. In addation, the fluorescence enhancement factor of the Rh6G is related to the size of the AAO pore. The second part:Fluorescence enhancement of Rh6G from silver nanoparticles modulated with porous anodic alumina template.Silver nanoparticles (SNPs) were formed in the porous anodic aluminum oxide (AAO) templates via oxid reduction method and a new type of AAO/SNPs nano-composite structure substrate was prepared. The fluorescence enhancement of Rh6G fiuorophore molecules on the AAO/SNPs nano-composite structure substrate was investigated with532nm CW laser excitation. The result demonstrated that the fluorescence enhancement on AAO/SNPs nanocomposite substrate was6times higher than on the undecorated AAO. It was also found that the fluorescence enhancement factor various with the size of the pore in AAO. The observed phenomenon was discussed based with the local electromagnetic (EM) field enhancement theory, and the advantages of periodically modulated SNPs in3-D with AAO template were explored. The third part:Fluorescence enhancement of Rh6G from gold nanoparticles were deposited on porous anodic alumina template.Gold nanoparticles were prepared by crystal seed method, then they were deposited on the porous anodic aluminum oxide (AAO) templates via physical deposition method and a new type of AAO/Au nano-composite structure substrate was prepared. The fluorescence enhancement of Rh6G fluorophore molecules on the AAO/Au nano-composite structure substrate was investigated with532nm CW laser excitation.The result demonstrated that AAO/Au nano-composite structure substrate have a slightly better fluorescence enhancement, the enhancement factor can arrived2.5times compared with undecorated AAO. In addation, the fluorescence enhancement factor was rely heavily on the time of physical deposition, the size of AAO pore. Discussed and analysed the fluorescence enhancement and quenching phenomena with local field enhancement theory and energy transfer theory.