非球形金纳米颗粒光学特性及粒径浓度测量

发布时间：2018-04-04 20:11

本文选题：金纳米棒颗粒　切入点：局域表面等离激元共振　出处：《西安电子科技大学》2016年硕士论文

【摘要】：金纳米颗粒表现出与体相材料所不同的特殊光学特性。金纳米颗粒具有局域表面等离激元共振现象,对特定波长呈现强烈的光吸收和散射特性。基于这些独特的光学特性,金纳米颗粒在生物、医学、化学、信息、能源、环境等众多领域得到广泛应用。深刻认识非球形金属纳米颗粒光学特性变化规律对于它在实际中的应用有重要的指导意义。金属纳米颗粒的粒径和浓度决定着它在实际应用中的性质和行为,光谱消光法是一种简单、低成本并能实现实时在线测量的颗粒粒度测量方法,它有望应用于非球形颗粒的粒径和浓度参数测量。非球形金属纳米颗粒中金纳米棒颗粒因其制备技术成熟、共振峰谐调波长范围广、极大的光学吸收、散射截面,和很高的光热转换效率,使得它成为非球形金属纳米颗粒中应用最广泛的纳米颗粒。本文将选取金纳米棒颗粒作为非球形金纳米颗粒的典型研究颗粒。用于计算非球形颗粒散射问题的方法中,T矩阵方法具有计算速度快、计算尺寸参数大、精度高的优点,且此方法的程序代码开源,使用方便,便于修改。基于此本文增加了目前T矩阵方法中没有的棒状模型。本文利用T矩阵方法结合介电函数的尺寸修正模型,系统地定量研究了几种常见金纳米颗粒(金纳米椭球、纳米圆柱和纳米棒)的几何尺寸和周围介质对其消光谱共振峰位置和强度的影响,总结了共振波长和强度的变化规律,得到金纳米棒具有最广的共振峰调谐范围。针对金纳米棒在光热治疗和生物成像中的应用,采用T矩阵方法定量研究了金纳米棒的尺寸对共振光吸收与后向散射特性的影响,通过最大化体积吸收系数和体积后向散射系数获得的金纳米棒优化尺寸可同时应用于光热治疗和生物成像中。最后把光谱消光法引入到金纳米棒颗粒系的粒径分布和浓度测量,光谱消光法通过测量不同波长下颗粒系的消光值,可同时反演颗粒系粒径分布和浓度分布。测量得到金纳米棒样品的实验室消光谱,借鉴球形颗粒的反演方法,反演获得了金纳米棒的直径、长度分布和颗粒数浓度,反演结果与样品标准值吻合较好。
[Abstract]:Gold nanoparticles exhibit special optical properties different from bulk materials.Gold nanoparticles exhibit strong optical absorption and scattering characteristics for specific wavelengths due to the local surface isoexciton resonance phenomenon.Based on these unique optical properties, gold nanoparticles are widely used in many fields, such as biology, medicine, chemistry, information, energy, environment and so on.A deep understanding of the optical properties of non-spherical metal nanoparticles is of great significance for its practical application.The particle size and concentration of metal nanoparticles determine their properties and behaviors in practical applications. Spectral extinction method is a simple, low-cost and real-time on-line measurement method for particle size measurement.It is expected to be applied to the measurement of particle size and concentration parameters of non-spherical particles.The gold nanorods in non-spherical metal nanoparticles have a wide range of resonant wavelength tuning due to their mature preparation technology, great optical absorption, scattering cross section, and high photothermal conversion efficiency.It has become the most widely used nanoparticles in non-spherical metal nanoparticles.In this paper, gold nanorods are selected as typical non-spherical gold nanoparticles.The T-matrix method used to calculate the scattering problem of non-spherical particles has the advantages of high calculation speed, large size parameter and high precision. The program code of this method is open source, easy to use and easy to modify.Based on this, the rod-like model which is not found in the T matrix method is added in this paper.In this paper, by using the T matrix method and the size correction model of dielectric function, several kinds of gold nanoparticles (gold nanoscale ellipsoid) are studied quantitatively and systematically.The influence of geometry size and surrounding medium on the position and intensity of the resonance peak is summarized, and the variation of resonance wavelength and intensity is summarized. The results show that the gold nanorods have the widest tuning range of resonance peak.Aiming at the application of gold nanorods in photothermal therapy and biological imaging, the effects of the size of gold nanorods on the resonance light absorption and backscattering were quantitatively studied by using T-matrix method.The optimized size of gold nanorods obtained by maximizing the volume absorption coefficient and the volume backward scattering coefficient can be used in both photothermal therapy and biological imaging.Finally, the spectral extinction method is introduced to the particle size distribution and concentration measurement of gold nanorods. By measuring the extinction value of the particle system at different wavelengths, the particle size distribution and the concentration distribution can be retrieved simultaneously by the spectral extinction method.The experimental elimination spectra of gold nanorods were measured and the diameter, length distribution and particle number concentration of gold nanorods were obtained by using the inversion method of spherical particles. The inversion results were in good agreement with the standard values of the samples.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O614.123;TB383.1

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