毕业论文-金属纳米颗粒吸收与散射的理论模拟.docx

太原理工大学本科生学位论文  PAGE \* MERGEFORMAT I 金属纳米颗粒吸收与散射的理论模拟 摘 要 简要介绍了薄膜太阳能电池陷光技术的研究背景，并详细阐述纳米颗粒散射截面和吸收截面的理论模拟方法。利用Drude模型解释了表面等离子体的产生过程，并且介绍了表面等离子体的两种分类；论述了3种理论模型：米氏模型，Drude模型和Drude-Lorentz模型，同时对它们各自的优缺点、适用条件作了简要描述。之后利用有限元方法研究了金属纳米颗粒的形状、大小和衬底材料对光散射的影响。为了客观地分析纳米颗粒的光散射能力，对散射截面、吸收截面进行了模拟计算。COMSOL软件的计算数据证明：阻抗损失集中在球表面附近，并且由球心向表面逐渐递增。在短波长范围内一个单独的金球会沿入射波的传播方向向前散射。在更长的波长范围内，球的散射场看起来更像偶极天线的辐射模式。颗粒优先吸收更短的波长。通过改变球的半径研究吸收如何受几何形状的影响。随着球的半径的增加，颗粒吸收增强，引起热损失增大。极化角不变的情况下，吸收截面和消光截面受方位角的影响不明显。方位角不变的情况下，吸收截面和消光截面受极化角的影响较大，随着极化角的增大，吸收截面和消光截面减小。散射截面越大越好，有利于活性层的吸收。 关键词：表面等离子体，散射截面，吸收截面。  PAGE \* MERGEFORMAT VII THEORETICAL SIMULATION OF ABSORPTION CROSS SECTION AND THE SCATTERING CROSS SECTION OF METAL NANOPARTICLES ABSTRACT The research background of light trapping technology for thin solar cells was reviewed briefly, and the theoretical simulation method of the scattering cross section and absorption cross section of metal nanoparticles was introduced in detail. The explanation on the formation of the surface plasmon using Drude model, and two kinds of classification of surface plasma were introduced; Three theoretical models, Mie model, Drude model and Drude - Lorentz model, and their respective advantages and disadvantages, applicable conditions were described briefly. The influence of the shape and size of gold nanoparticles and its substrate material on light scattering was studied by the finite element method. In order to objectively analyze the light scattering ability of nanoparticles, the scattering cross section and the absorption cross section were calculated. The calculation data by COMSOL software prove that the impedance loss concentrated near the surface of the gold sphere, and increases gradually from the center to the surface. In the short wavelength range a single gold sphere will scatter forward along the spread of the incident wave direction. In the longer wavelength range, the scattering field pattern of the gold sphere look more like dipole antenna radiation. And