不同尺寸奈米金粒子的製備、光學特性與應用

Fabrication, Optical Characterization and Applications of Different Sized Gold Nanoparticles

李家瑋(Chia-Wei Lee)

指導教授 ： 陳敏璋

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.00979

摘要

(黃)金，原子序79，在元素周期表中的最後一列。由於其性質穩定，顏色艷麗，自古以來就一直與人類的日常生活息息相關，廣泛被使用作為容器、裝飾品、建築、貨幣……等。
金屬內部具有可任意移動的自由電子(d軌域電子)，當金屬由塊材縮小達奈米(10－9 m)尺度時，其電子運動因受到空間的侷限而產生獨特的物理及光學性質。金在可見光波長範圍內的介電係數為負值，因此奈米金顆粒在可見光內具有特徵的局部表面電漿共振(LSPR)吸收及散射。在本論文中，將利用奈米金的強散射性質作為顯影效果，搭配暗場光學切片顯微術(Dark-Field Optical Section Microscope, DFOSM)，成功的利用80 nm奈米金顆粒描繪出活細胞之表面形貌。更藉由此顯微術成功的即時觀察到非小型肺腺癌細胞(CL1-0)在加入細胞鬆弛素(Cytochalasin D)後形變之過程。
隨著製程及濕式化學合成技術的進展，目前已能將奈米結構的間距及奈米顆粒的大小縮小到數個奈米的等級。然而，當奈米顆粒縮小到僅由幾個原子所組成時(粒徑< 2奈米，亦可稱奈米團簇)，能階不再連續而產生’’類分子’’的性質。其中最引人注意的是金與銀奈米團簇在可見光波長範圍會產生穩定螢光的特性。在論文中，利用樹枝狀結構的高分子(PAMAM)成功的製備出具有八個金原子組成的金奈米團簇，並研究其作為載體來攜帶核酸進入活細胞的效率以及探討其對活細胞存活率的影響。
在科技發達的今日，除了疾病問題以外，能源短缺為首要必須解決的問題。利用半導體材料吸收太陽光而直接將水催化分解成氫氣及氧氣為目前熱門的研究題目。在論文中，選用氧化鎢奈米柱作為感光陽極，在陽極上鋪上一層奈米金顆粒將有效提升可見光範圍內催化水解反應的效率。並結合原子層沉積製程技術，在基板上沉積上一層氧化鋁以增加元件的穩定度。

關鍵字

金奈米顆粒 ； 侷部表面電漿共振 ； 暗場光學切片顯微術 ； 金奈米團簇 ； 氧化鎢 ； 光催化水分解 ； 原子層沉積

並列摘要

Gold (atomic number: 79), lies in the last row of the periodic table. It is closely related to human daily life since ancient times due to its brilliant color and stable characters. Gold is also extensively used to make pots, decorations, buildings, currencies….etc.
When the dimensions of metals are reduced to the nanometer scale, the freely moved d orbital electrons will be confined in space. The nanometer sized metals produce unique physical and optical properties other than the bulk materials. Gold nanoparticles have a significant localized surface plasmon resonance absorption and scattering in the visible light wavelength due to the negative dielectric constant in this range. In this thesis, we built a simple apparatus named as Dark-Field Optical Section Microscope (DFOSM). The live cell morphology was successfully reconstructed by recording the strong scattering signals from 80 nm sized gold nanoparticles. Using this microscopy, we can record real-time morphology changes of the human lung cancer cells (CL1-0) influenced by the actin polymerization inhabitor, Cytochalasin D.
The sizes and gaps of nanostructures now can be well controlled to few nanometers by the improved chemical fabrication techniques. However, when the sizes of nanoparticles keep reduced, only composed of few atoms, they behave‘’molecule-like’’properties and also called as nanoclusters. The most interesting property of Au nanoclusters (size < 2 nm) is its tunable fluorescence in the visible light range. In this thesis, we fabricated the fluorescent Au nanoclusters capped by dendrimers (Au8@PAMAM), and used it as a gene carrier and investigated the transfection efficiencies in various type of cells.
Nowadays, besides the evolutionary diseases, the short in energy supply is another top issue arises from the fast developed civilization. Water splitting is a popular research on energy storage. It is a process of directly converting water into hydrogen and oxygen. The absorbed solar energy is stored as chemical energy by the catalytic property from semiconductor materials. In this thesis, we fabricated tungsten oxide nanorods as photo anode. By depositing gold nanoparticles onto the anodes, the conversion efficiency is enhanced in the visible light range. Finally, the stability of the photo anodes was improved by depositing an aluminum oxide thin film through the atomic layer deposition technique.

並列關鍵字

gold nanoparticles ； localized surface plasmon resonance (LSPR) ； dark-field optical section microscope (DFOSM) ； gold nanocluster ； tungsten oxide (WO3) ； photocatalytic water splitting ； atomic layer deposition (ALD)

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