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  • 學位論文

一 .在水相中以植晶法合成銀奈米立方晶體 二.用銀立方體製備金籠及其光熱效應

Seed-Mediated Growth of Silver Nanocubess in Aqueous Solution II. Formation of Au Nanocages from Ag nanocubes and Their Photothermal Effect

指導教授 : 黃暄益
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摘要


一、 在水相中以植晶法合成銀奈米立方晶體 在本研究當中,我們使用植晶方法在水相系統中製備邊長為23-60 nm的銀奈米立方體。氯化十六烷基三甲基銨鹽和三氟乙酸銀會形成氯化銀,維生素C還原氯化銀形成銀奈米立方體。也可採用另一個植晶方法合成銀奈米立方體,在成長溶液中加入硝酸銀當作銀的來源、硫酸銅調控氧化還原反應、溴化十六烷基三甲基銨鹽當保護劑及維生素C當作還原劑。藉由粉末X光繞射鑑定、穿透式電子顯微鏡電子繞射鑑定與掃描式電子顯微鏡影像拍攝可了解銀奈米立方體的結構。可見光吸收光譜提供粒子大小對光譜變化的鑑定。 二、 用銀立方體製備金籠及其光熱效應 本研究中使用銀奈米立方體當作模板加入氯金酸在30℃下反應10分鐘合成方形金籠。使用伽凡尼取代反應,銀立方體被氧化,同時金源會還原在晶體表面上。當加入不同量的氯金酸於含有氯化十六烷基三甲基銨鹽和銀奈米立方體的成長溶液時,粒子形貌和其金與銀的原子比例會有所改變。使用金籠在照波長808奈米且為1.47瓦特的雷射,具不同吸收波長的銀金合金籠溫度會快速上升到90℃, 95℃, 和 100℃。用波長1064奈米的雷射加熱時效率很低。使用金籠發展的光熱效應可以應用在加熱水產生能源。

關鍵字

銀立方體 金籠 光熱效應

並列摘要


CHAPTER 1 Seed-Mediated Growth of Silver Nanocubess in Aqueous Solution In this work, we have developed a seed-mediated approach to synthesize Ag nanocubes with average edge lengths from 23 nm to 60 nm. Ag seed solution is added a growth solution containing CF3COOAg, cetyltrimethylammonium chloride (CTAC), and ascorbic acid. Ag nanocubes are synthesized by using ascorbic acid as reducing agent to reduce AgCl in the presence of CTAC. We have also used another method to synthesize Ag nanocubes. This approach involves adding the seed solution to a growth solution containing AgNO3, cetyltrimethylammonium bromide (CTAB), CuSO4 and ascorbic acid. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) patterns have been employed to characterize the Ag nanocubes. UV‒vis absorption spectra of the particles have been obtained. CHAPTER 2 Formation of Au Nanocages from Ag Nanocubes and Their Photothermal Effect In this study, we have used Ag nanocubes as templates to synthesize Au nanocages by adding HAuCl4 at 30 ºC for 10 minutes. This involves galvanic replacement reaction. Ag nanocubes are oxidized and AuCl4‒ is reduced to Au and deposited on the surface of Ag nanocubes. When different amounts of HAuCl4 were added to a growth solution including Ag nanocubes and CTAC, the morphology and Au/Ag ratio can vary. We used the cages to investigate photothermal effect. Using different cages, the solution temperature can rise to 90, 95 and 100ºC under the illumination of an 808 nm laser with 1.47 W. Use of a 1064 nm laser led to a lower heating efficiency. These cages may find applications including heat generation for as an energy source.

參考文獻


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CHAPTER 1
Seed-Mediated Growth of Silver Nanocubess in Aqueous Solution
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