Microemulsion-based synthesis of nanoscaled silver hollow spheres and direct comparison with massive particles of similar size.
Microemulsion-based synthesis of nanoscaled silver hollow spheres and direct comparison with massive particles of similar size.
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DOI：
10.1039/c0nr00291g
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发表时间：
2010-10
期刊：
影响因子：
6.7
通讯作者：
C. Kind;R. Popescu;E. Müller;D. Gerthsen;C. Feldmann
中科院分区：
文献类型：
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作者：
C. Kind;R. Popescu;E. Müller;D. Gerthsen;C. Feldmann
首先采用微乳液法制备了外径为15-20 nm、壁厚为3-5 nm、内腔直径为10-15 nm的纳米级银空心球。通过电子显微镜（SEM, BF-/HAADF-STEM， HRTEM）和x射线衍射（线形分析）证实了空心球体的存在，以表征微晶性质。除了空心球体之外，通过微乳液还可以获得类似大小（外径15-20纳米）的大质量银纳米颗粒。基于实验条件和所得粒子尺寸的相似性，用制备的银空心球和大质量纳米粒子比较了它们的光学性质和表面等离子体共振。与减小大质量粒子的直径相反，银纳米粒子的“空穴”会导致等离子体共振的红移。在空心球的情况下，红移约为33纳米，确实观察到量子尺寸效应，并且与薄球壁一致。
Nanoscale silver hollow spheres are first prepared via a microemulsion approach with 15-20 nm as the outer diameter, 3-5 nm as the wall thickness, and 10-15 nm as the diameter of the inner cavity. The presence of hollow spheres is confirmed by electron microscopy (SEM, BF-/HAADF-STEM, HRTEM) as well as by X-ray diffraction with a line-shape analysis to characterize the microcrystalline properties. In addition to the hollow spheres, massive silver nanoparticles of similar size (outer diameter of 15-20 nm) are gained via microemulsions. Based on the similarity of experimental conditions and the resulting particle size, as-prepared silver hollow spheres and massive nanoparticles are used to compare their optical properties and surface-plasmon resonance. In contrast to reducing the diameter of massive particles, "hollowing" of silver nanoparticles leads to a red-shift of the plasmon resonance. With a red shift of about 33 nm in the case of the hollow spheres, a quantum-size effect is indeed observed and in accordance with the thin sphere wall.