https://scholars.lib.ntu.edu.tw/handle/123456789/81637
Title: | 金奈米桿結構之光學特性分析 Optical Properties of Gold Nanorods |
Authors: | 李承諭 Lee, Cheng-Yu |
Keywords: | 金奈米桿;金奈米橢球;表面電漿共振;多重中心展開法;螢光增益;吸收截面積;散射截面積;消光截面積;量子效率;gold nanorods;gold nano ellipsoids;SPR;MMP;fluorescence enhancement;absorption cross section;scattering cross section;extinction cross section;quantum yield | Issue Date: | 2010 | Abstract: | 在金奈米粒子表面放一螢光分子,打入平面電磁波時,可使奈米粒子產生表面電漿效應。在奈米粒子的表面激發很強的電場,使螢光分子達到激發態,而螢光分子由激發態返回基態的過程中,會產生螢光增益的效果。本研究主要是探討不同幾何結構的金奈米粒子對螢光增益的影響。 本研究依據Maxwell電磁理論,利用多重中心展開法,探討研究三維金奈米桿在空氣中或水中時,入射平面電磁波或電偶極波源後的電磁場。同時利用這些電磁場去求得奈米粒子之吸收截面積、散射截面積、消光截面積、輻射效率、非輻射效率、量子效率和螢光增益。在文中探討了單顆的金奈米橢球與金奈米桿,以及直列結構的金奈米橢球與金奈米桿,還有不同的夾角的雙顆金奈米桿,以及Y字形結構金奈米桿之螢光增益現象與吸收散射消光截面積。 結果發現,同樣大小與長短比下,金奈米桿的效率會比金奈米橢球來的好。直列結構的金奈米桿的螢光增益會比單顆時強了五倍以上。Y字形結構的金奈米桿在吸收、散射、消光截面積的部分,幾乎不受平面電磁波的極化方向影響,在螢光增益部分,最弱的螢光增益倍數,依然還有超過一倍的效率。 If a fluorescence molecule is placed in the proximity of gold nanoparticles and impinged by a plane wave, the surface plasmon resonance will be produced. The gold nanoparticles will excite very strong electric field by the surface plasmon resonance effect. The strong excited electric field will cause fluorescence enhancement effect on the fluorescence molecule. This research primarily emphasizes on studying the difference in fluorescence enhancements between different geometric structures of gold nanoparticles. This study is based on Maxwell electromagnetic theory. By using the method of multiple multipole expansion, this study focuses on the electromagnetic fields of three dimensional gold nanorods. Absorption cross section, scattering cross section, extinction cross section, radiative decay rate, nonradiative decay rate, quantum yield, and fluorescence enhancement factor of gold nanorods are then calculated. The structures considered in this thesis include: single gold nanorod (and nano-ellipsoid), aligned gold nanorods (and nano-ellipsoids), nonaligned gold nanorods and Y-shaped gold nanorods. The result shows that when the size and aspect ratio of gold nanorods and gold nano ellipsoids are the same, the efficiency of gold nanorods is better. The fluorescence enhancement factor of aligned gold nanorods is five times the single. The absorption cross section, scattering cross section and extinction cross section of Y-shaped gold nanorods are almost unchanged when the polarization of planewave changes. While in the weakest case, the fluorescence enhancement factor of Y-shaped gold nanorods is still more than one time. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/249997 |
Appears in Collections: | 應用力學研究所 |
File | Description | Size | Format | |
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ntu-99-R97543048-1.pdf | 23.53 kB | Adobe PDF | View/Open |
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