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金纳米粒子生长的原位观察
In-situ observations of the growth of the gold nanoparticles |
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| 课程网址: |
http://videolectures.net/ipssc2017_ambrozic_gold_nanoparticles/
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| 主讲教师: |
Bojan Ambrožič
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| 开课单位: |
约瑟夫·斯特凡学院
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| 开课时间: |
2017-03-23
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| 课程语种: |
英语
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| 中文简介: |
金纳米粒子是一种用途广泛的材料，它在许多其他应用中也被用于实验性癌症治疗，其中金纳米粒子的光热效应[1]。因此，金纳米粒子的成核过程和化学反应动力学需要在高温条件下在液体中得到很好的理解[2]。在我们的实验中，使用1.5毫米的三水金（III）水溶液（氯金酸）作为金的来源。实验使用Jeol-jem2100透射电子显微镜（TEM）在200千伏电压下与液体电池结合进行。在108 Gy/s的电子剂量下观察样品。首先在室温（25°C）下观察样品几分钟，证明溶液在这些条件下是稳定的。之后，将样品加热至50°C。30 s后，开始出现5-10纳米大小的纳米颗粒（NPs）。纳米粒生长了2.5分钟，在这一点上达到了30-60纳米的最终尺寸。之后，金单体在核动力源周围又生长了3分钟。在最后的阶段：核动力源粒子确实在一个更大的单个团簇中结合。选择性电子衍射分析证实了面心立方晶体结构。我们认为金纳米粒子的形成是一个4步的过程。第一步是种子粒子的形成，这可以解释为金前体的部分还原。接下来是在种子颗粒周围生长的金氢氧化物。在第三步和第四步中，所有的铰孔金都被还原，从而导致核动力源由内向外生长和合并。
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| 课程简介: |
Gold nanoparticles are versatile material, which is among many others applications also used in experimental cancer treatment where gold nanoparticle`s phototermal effect [1] is employed. For that reason gold nanoparticle`s nucleation processes and chemical reaction kinetics need to be well understood in-situ in liquid at the elevated temperature conditions [2]. In our experiment 1.5 mM water solution of gold(III) chloride trihydrate (chloroauric acid) as source of gold was used. The experiment was performed using Jeol JEM 2100 transmission electron microscope (TEM) operated at 200 kV combined with the liquid cell. The sample was observed at an electron dose of 108 Gy/s. Firstly the sample was observed for several minutes at the room temperature (25 °C), proving the solution is stable at these conditions. After that the sample was heated to 50 °C. After 30 s 5-10 nm sized nanoparticles (NPs) started to appear. The NPs grew for a period of 2.5 min and at this point reached the final size of 30-60 nm. After that gold monomers grow around NPs for further 3 min. In the final the stage: NPs particles did coalesce in a larger individual clusters. Selective electron diffracting analysis proved the face centered cubic crystal structure. We are suggesting that the formation of gold nanoparticles is a 4-step process. First step is the formation of seed particles, which could be explained by partial reduction of the gold precursors. This is followed by the growth of the golden hydroxide around the seed particle. In the third and fourth step all the reaming gold is reduced, which results in the inside-out growth and coalescence of the NPs.
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| 关 键 词: |
纳米; 生长; 观察
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| 课程来源: |
视频讲座网
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| 数据采集: |
2020-11-26：yxd
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| 最后编审: |
2020-12-18：yumf
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| 阅读次数: |
46
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