金属薄膜上颗粒二聚体中的能量聚集效应研究

发布时间：2018-05-25 22:34

本文选题：表面等离激元 + 局域表面等离激元　；参考：《重庆大学》2016年硕士论文

【摘要】：纳米金属结构在有入射光照射的情况下,其表面存在自由电子集体振荡的模式,这种表面模式被称之为表面等离激元(Surface Plasmonic Polaritons,SPPs)。由于它能将电磁场束缚在亚波长范围内,所以其金属结构表面会有很强的电磁增强。在纳米金属颗粒上,由于其局域表面等离激元,会存在非常强的电磁场能量。这种电磁场能量常被广泛运用于表面增强拉曼散射、光催化、太阳能电池、光致发光、传感器等。然而电磁场能量的分布与其对应的金属大小,形状及入射光的波长紧密相关,这就促使我们去研究各种各样结构的金属。在熟悉、掌握模拟计算软件的过程中,我们研究了各种结构的纳米金属的表面等离激元及它的运用,月牙形状、颗粒-膜结构、纳米颗粒-线/膜结构。在这些不同结构的纳米金属中,它们展现了不同的现象,都有了各自的不同应用发展。在实验室中,科研者用化学合成方法合成纳米金属颗粒已成为主流的今天,研究异质二聚体-膜结构具有现实指导意义。在许多高校中,实验者利用化学合成的方法制备的二聚体通常均匀性不够,导致很多研究者在探测二聚体相应信号时,实际上所探测到的信号为异质二聚体的信号。在当下,各种金属、非金属颗粒-膜结构成为等离激元方面研究的主流之一,而对异质二聚体-膜结构的研究较少,对实际实验室中二聚体的不均匀性导致形成的异质二聚体及对二聚体所造成的影响研究更为少见。本文在研究了月牙形状、颗粒-膜结构、纳米颗粒-线/膜结构的表面等离激元及它们的运用后,就实验室这种实验制备的普遍行对异质二聚体-膜结构进行研究,讨论这种异质二聚体-膜结构导致的能量重新分布及此结构对二聚体-膜结构所探测的信号所带来的影响。最开始,此论文从用有限元方法(Finite element method,FEM)模拟得到的异质二聚体-膜结构具有能量聚集效应开始,发现在2Ag-Au这种异质二聚体-膜模型中,小Ag纳米颗粒把能量聚集在Ag颗粒与Au膜之间细缝的能力比大Ag纳米颗粒的要更强,甚至前者能力能达到后者能力的五倍多。而后,此文章又指出更多的模拟结果表明在异质二聚体-膜的2Ag-Au模型中表现的能量聚集能力与激发光的波长和两个Ag纳米颗粒的比例有很强的依赖关系。接着研究了激发光的波长对2Ag-Au模型展现出来的能量聚集能力的影响。随后讨论了在2Ag-Au模型中,两个Ag纳米颗粒的比例对模型的聚集能量能力的影响。后来,本文章提出在Ag纳米颗粒、Ag纳米线-Au膜的模型中也存在相似的聚集能力,并指出从这种模型中测出的表面增强拉曼散射SERS光谱为我们模拟计算得到的理论预期提供了实验论证。讨论了所测SERS光谱的信号实际更多会来自小Ag纳米颗粒。而在现实实验测量中,许多研究者都忽视了此种情况带来的影响。本文研究的结果使我们对纳米颗粒-膜体系的表面等离激元性质理解更多,并对等离激元相关领域有现实应用价值。
[Abstract]:There is a mode of free electron collective oscillation on the surface of the nanostructure with incident light, which is called the surface plasmon (Surface Plasmonic Polaritons, SPPs). Because it can bind the electromagnetic field to the subwavelength range, the surface of the metal structure will have a strong electromagnetic enhancement. There is a very strong electromagnetic field energy on the mica metal particles, because of its local surface and other excitations. This electromagnetic field is often used widely in surface enhanced Raman scattering, photocatalysis, solar cells, photoluminescence, sensors and so on. However, the distribution of electromagnetic field energy is closely related to the size, shape and wavelength of the incident light. Closely related, this prompted us to study all kinds of metal structures. In the process of familiarity and mastery of analog computing software, we studied the surface plasmon and its application of various structures of nanometers, the shape of the crescent, the particle film structure, the nanoparticle line / membrane structure. In these different structures, they spread in the nanoscale metal. In the laboratory, researchers use chemical synthesis method to synthesize nano metal particles in the laboratory. In the laboratory, the study of heterogeneous two polymer membrane structure has practical guiding significance. In many universities, the experimenters use the method of chemical synthesis to make the two polymer usually homogeneity. Not enough, many researchers in the detection of the corresponding signal of the two polymer, in fact, the detected signal is the signal of heterogeneous two polymer. In the present, all kinds of metal, non metal particle membrane structure become one of the mainstream of the study of the plasmons, but the study of heterogeneous two polymer membrane structure is less, and the two polymer in the actual laboratory is not. The study of the shape of the crescent tooth, the particle film structure, the surface plasmons of the nanoparticle line / membrane structure and their application are studied in this paper, and the study of the heterogeneous two polymer membrane structure is discussed in the laboratory. The energy redistribution caused by this heterostructure two polymer membrane structure and the effect of this structure on the signals detected by the two polymer membrane structure. First, the heterogeneous two polymer membrane structure obtained by the finite element method (Finite element method, FEM) has the beginning of the energy accumulation effect, and it is found in the 2Ag-Au heterostructure two. In the polymer film model, the ability of small Ag nanoparticles to gather energy between Ag particles and Au films is stronger than that of large Ag nanoparticles. Even the former ability can reach five times the capacity of the latter. The wavelength of stimulated luminescence has a strong dependence on the proportion of the two Ag nanoparticles. Then the influence of the wavelength of the excited luminescence on the energy aggregation ability of the 2Ag-Au model is investigated. Then, the influence of the proportion of the two Ag nanoparticles on the aggregation energy of the model in the 2Ag-Au model is discussed. Later, this article proposed in Ag Na Rice particles, Ag nanowires -Au films also have similar aggregation ability, and point out that the surface enhanced Raman scattering SERS spectra obtained from this model provide an experimental demonstration of the theoretical expectation obtained by our simulation. It is discussed that the signal of the SERS spectrum measured is more likely to come from the small Ag nanoparticles. In this case, many researchers ignore the effect of this situation. The results of this study make us more understanding of the properties of the surface plasmon polaritons in the nanoparticle membrane system, and have practical application value in the field of peer-to-peer ionization.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O53;TB383.1

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