Preparation and optical characterization of core-shell bimetal nanoparticles
Preparation and optical characterization of core-shell bimetal nanoparticles
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DOI：
10.1007/s11468-005-9000-5
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发表时间：
2006-03-01
期刊：
影响因子：
3
通讯作者：
Fritzsche, W.
中科院分区：
文献类型：
--
作者：
Steinbrueck, A.;Csaki, A.;Fritzsche, W.
化学方法允许合成高度限定的金属异质纳米结构，例如核-壳纳米球。因为金属纳米颗粒中的材料决定了等离子体共振诱导的吸收带，所以控制颗粒组成导致控制吸收带的位置。在金或银纳米颗粒上沉积金属产生具有改性光学性质的核-壳颗粒。对溶液生长的以及表面生长的颗粒进行紫外-可见光谱，并提供溶液中的系综测量。增加第二金属的层导致吸收带的移动。与原始粒径相当的壳直径导致壳材料的主要影响。壳生长的程度可以通过反应时间或金属盐或还原剂的浓度来控制。除了光学表征，利用原子力显微镜，扫描电子显微镜，透射电子显微镜产生了重要的信息纳米复合物的超微结构。表面生长的核-壳颗粒在可获得的壳厚度方面是上级的，因为溶液生长的颗粒由于盐诱导的聚集而遇到困难。
Chemical approaches allow for the synthesis of highly defined metal heteronanostructures, such as core-shell nanospheres. Because the material in the metal nanoparticles determines the plasmon resonanceinduced absorption band, control of particle composition results in control of the position of the absorption band. Metal deposition on gold or silver nanoparticles yielded core-shell particles with modified optical properties. UV-vis spectroscopy on solution-grown, as well as surface-grown, particles was conducted and provided ensemble measurements in solution. Increasing the layers of a second metal leads to a shift in the absorption band. A shell diameter comparable to the original particle diameter leads to a predominant influence by the shell material. Extent of shell growth could be controlled by reaction time or the concentration of metal salt or reducing agent. Besides optical characterization, the utilization of atomic force microscopy, scanning electron microscopy, and transmission electron microscopy yielded important information about the ultrastructure of nanoparticle complexes. Surface-grown core-shell particles were superior in terms of achievable shell thickness, because of difficulties encountered with solution-grown particles due to salt-induced aggregation.