Carbone Luigi, Kudera Stefan, Carlino Elvio, Parak Wolfgang J, Giannini Cinzia, Cingolani Roberto, Manna Liberato
National Nanotechnology Laboratory of CNR-INFM, 73100 Lecce, Italy.
J Am Chem Soc. 2006 Jan 25;128(3):748-55. doi: 10.1021/ja054893c.
Branching in semiconductor nanocrystals, which leads to tetrapods and to more complex architectures, is the subject of intensive investigation. Here we support the model according to which branching in CdTe nanocrystals is driven by the formation of multiple wurtzite twins. This is in contrast to previous models for this material. We found that twinning, as well as anisotropic growth, can be triggered by the presence of suitable molecules, such as for instance methylphosphonic acid. In the case of CdTe nanocrystals, we designed a robust growth scheme in which the variation of a single parameter (the concentration of methylphosphonic acid in solution) leads to the controlled formation of nanocrystals with shapes ranging from spheres to anisotropic structures with varying level of branching, as both twinning and anisotropic growth are progressively favored. We believe that these concepts can be extended to other nanocrystal systems.
半导体纳米晶体中的分支现象可形成四足状及更复杂的结构，这是当前深入研究的课题。在这里，我们支持这样一种模型，即碲化镉纳米晶体中的分支是由多个纤锌矿孪晶的形成所驱动的。这与该材料先前的模型不同。我们发现，孪晶以及各向异性生长可以由合适分子的存在引发，比如甲基膦酸。对于碲化镉纳米晶体，我们设计了一种稳健的生长方案，其中单一参数（溶液中甲基膦酸的浓度）的变化会导致可控地形成形状从球形到具有不同分支程度的各向异性结构的纳米晶体，因为孪晶和各向异性生长都逐渐受到促进。我们相信这些概念可以扩展到其他纳米晶体系统。
