光子晶体与金属纳米复合体系的光学增强效应研究

发布时间：2018-05-11 18:06

本文选题：光子晶体 + 表面等离激元　；参考：《西南大学》2015年硕士论文

【摘要】：近年来,微纳光子学引起了人们的广泛研究,提高光与物质作用过程中的光利用效率并实现在微纳尺度上对光的操控是研究的重点,其中两个十分热门的研究方向是光子晶体和表面等离激元。光子晶体因其特殊的周期性结构而具有光子带隙特性,从而可以对特定频率光的传播进行操控。表面等离激元具有表面局域和近场增强的特性,也能够在纳米尺度上调制附近的电磁信号。光子晶体和表面等离激元的特性使其在表面增强拉曼散射和荧光增强方面有广泛的应用。将光子晶体和表面等离激元相结合起来的研究具有非常重要的学术价值和现实意义,因此本文开展了光子晶体与金属纳米复合体系的光学增强效应研究。本文的主要研究内容和结论如下：(1)以苯乙烯为单体,甲基苯烯酸为稳定剂,过硫酸钾为引发剂,采用乳液聚合法合成了聚苯乙烯微球。通过调节单体、稳定剂和表面活性剂的用量实现’了对聚苯乙烯微球粒径和单分散性的调节。通过胶体自组装法,制备了具有不同光子带隙的光子晶体薄膜。(2)通过胶体共组装、高温煅烧和离子束溅射制备了光子晶体与银纳米复合基底,对吸附在该复合基底表面的R6G分子的拉曼信号进行检测,发现该基底使R6G分子的拉曼信号显著增强,银厚度为20nm的复合基底检测限为10-9mol/L,银厚度为80nm的复合基底检测限为10-8mol/L,但复合基底存在干扰峰。以溶剂腐蚀法代替高温煅烧法制备的复合基底除去了自身的干扰峰,该方法制备的复合基底(银厚度为20nm和80nm)检测限均为10-7mol/L。这些复合基底都具有高密度的“热点”结构,因此相比于空白玻璃基底和银基底来说,检测灵敏度均有了明显的提升。(3)对具有不同光子带隙的聚苯乙烯光子晶体先进行硅烷化或疏水化处理,后经离子束溅射制备了光子晶体与银纳米复合基底。以量子产率高的RhB作为荧光物质,复合基底、光子晶体基底均显著提高了RhB的荧光强度。其中,表面疏水化处理的光子晶体基底荧光增强效果最好,跟石英基底相比最高可以增强荧光强度2486倍。以量子产率较低的MPS-PPV作为荧光物质,复合基底、光子晶体基底也都显著的提高了其荧光强度。其中,未经疏水化处理的复合基底的荧光增强效果最好,跟石英基底相比最高可以增强荧光强度165倍。产生荧光强度大幅度提升的原因是,表面等离激元使激发效率提高并使辐射衰减速率增加,以及光子晶体能够抑制自发辐射。其中,表面等离激元的增强效应对量子产率低的荧光物质效果更显著。
[Abstract]:In recent years, micro-nano photonics has been widely studied. The emphasis of the research is to improve the efficiency of light utilization in the process of interaction between light and matter and to realize the manipulation of light at micro-nano scale. Two of the most popular research directions are photonic crystals and surface isopherons. Photonic crystals have photonic band gap because of their special periodic structure, which can control the propagation of light at specific frequencies. The surface isotherms have the characteristics of local and near field enhancement, and can modulate the nearby electromagnetic signals at nanometer scale. Photonic crystals and surface excitators are widely used in surface-enhanced Raman scattering and fluorescence enhancement. It is of great academic value and practical significance to study the combination of photonic crystals and surface isopotons. Therefore, the optical enhancement effect of photonic crystal / metal nanocomposites has been studied in this paper. The main contents and conclusions of this paper are as follows: (1) Polystyrene microspheres were synthesized by emulsion polymerization with styrene as monomer, methyleenoic acid as stabilizer and potassium persulfate as initiator. The particle size and monodispersity of polystyrene microspheres were adjusted by adjusting the amount of monomer, stabilizer and surfactant. Photonic crystal thin films with different photonic band gaps were prepared by colloidal self-assembly method. Photonic crystals and silver nanocomposite substrates were prepared by colloid co-assembly, high temperature calcination and ion beam sputtering. The Raman signal of R6G molecule adsorbed on the surface of the composite substrate was detected. It was found that the Raman signal of R6G molecule was significantly enhanced by the substrate. The detection limit of the composite substrate with silver thickness of 20nm is 10-9 mol / L, and the detection limit of the composite substrate with silver thickness of 80nm is 10-8 mol / L, but the interference peak exists in the composite substrate. The complex substrate prepared by solvent corrosion instead of high temperature calcination method removes its own interference peak. The detection limit of the composite substrate (silver thickness is 20nm and 80 nm) is 10 ~ (-7) mol / L ~ (-1). These composite substrates have high density "hot spot" structures, so compared with blank glass substrates and silver substrates, The sensitivity of polystyrene photonic crystals with different photonic band gaps was firstly silanized or hydrophobically treated, and then the composite substrate of photonic crystals and silver nanocrystals was prepared by ion beam sputtering. Using RhB with high quantum yield as fluorescence material, the fluorescence intensity of RhB was significantly increased by the combination of the substrate and the photonic crystal substrate. The photonic crystal substrate with surface hydrophobic treatment has the best fluorescence enhancement effect, and the highest fluorescence intensity can be enhanced by 2486 times compared with quartz substrate. Using MPS-PPV with low quantum yield as the fluorescent substance, the fluorescence intensity of the composite substrate and the photonic crystal substrate are improved significantly. The fluorescence enhancement of the composite substrate without hydrophobic treatment was the best, and the fluorescence intensity of the composite substrate was 165 times higher than that of the quartz substrate. The reason for the significant increase in fluorescence intensity is that the surface isotherm increases the excitation efficiency and the radiation decay rate, and the photonic crystal can suppress the spontaneous emission. Among them, the enhancement effect of surface isotherm is more significant for the fluorescence with low quantum yield.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O734;TB33

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