Department of Chemistry, University of California , Davis, California 95616, United States.
J Am Chem Soc. 2014 Jan 29;136(4):1296-9. doi: 10.1021/ja412213q. Epub 2014 Jan 14.
Creating allotropes and polymorphs of nanoparticles (NPs) has gained tremendous momentum in recent times. Group 14 (C, Si, Ge) has a number of allotropes; some with significant applications. Here we report the synthesis of Si NPs crystallizing in the BC8 structure via a colloidal route for the first time. The BC8 structure is a metastable structure of Si that can be accessed from the β-Sn form through the release of high pressure. These Si BC8 structured NPs were synthesized via reduction of SiI4 with n-butyllithium, capped with octanol and precipitated from solution. The transmission electron microscopy lattice fringes as well as the selected area electron diffraction pattern of the precipitate are consistent with the BC8 structure. The LeBail whole profile fitting of powder X-ray diffraction data also confirms the structure as the BC8 phase. The Raman spectrum provides further evidence to support the BC8 structure. With proper tuning of the band gap these NPs could be potential candidates for solar cells.
近年来，创造纳米粒子（NPs）的同素异形体和多晶型体已经取得了巨大的进展。第 14 族（C、Si、Ge）有许多同素异形体；其中一些具有重要的应用。在这里，我们首次报道了通过胶体途径合成具有 BC8 结构的 Si NPs。BC8 结构是 Si 的亚稳结构，可以通过释放高压从β-Sn 形式获得。这些 Si BC8 结构 NPs 是通过 SiI4 与正丁基锂还原反应合成的，用辛醇封端，并从溶液中沉淀出来。沉淀物的透射电子显微镜晶格条纹和选区电子衍射图谱与 BC8 结构一致。粉末 X 射线衍射数据的 LeBail 全谱拟合也证实了该结构为 BC8 相。拉曼光谱提供了进一步的证据支持 BC8 结构。通过适当调整带隙，这些 NPs 可能成为太阳能电池的潜在候选材料。
