在纳米晶体超级网格中存在大小依赖的多重结合
Sara M Rupich1, Elena V Shevchenko, Maryna I Bodnarchuk
1Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|December 9, 2009
概括
硫化 (PbS) 纳米晶体超晶体的大小影响其结构. 较大的PbS纳米晶体形成具有独特对称性的多重双胞胎超级格子,而较小的则没有.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术 纳米技术
- 晶体学 晶体学是指结晶学.
背景情况:
- 体纳米晶体自组装成有序的超级格子.
- 这些超级格子的形态和对称性对于它们的特性至关重要.
- 了解控制超级格子形成的因素是材料设计的关键.
研究的目的:
- 为了研究纳米晶体大小对硫化 (PbS) 超形态的影响.
- 阐明观察到的大小依赖的结构变化背后的机制.
- 探索设计具有可调节性质的新材料的含义.
主要方法:
- 不同尺寸 (<4 nm和>7 nm) 的单分散PbS纳米晶体的合成.
- PbS纳米晶体的自我组装成超级晶格.
- 使用电子显微镜和衍射技术对超级晶格形态和对称性的描述.
主要成果:
- 由大型PbS纳米晶体 (>7 nm) 形成的超级格子表现出多重生面中心立方结构,具有十面体和二面体对称性.
- 这些大型纳米晶体超级格子显示了由于多重生而在晶体学上被禁止的五倍对称元素.
- 由小PbS纳米晶体 (<4 nm) 组成的超级网格没有显示任何生.
- 发现双胞胎能量强烈依赖于大小,随着纳米晶体大小的增加而减少.
- 较大的纳米晶体具有较软的粒子间潜力,有利于形成多重双胞胎超级晶格.
结论:
- 纳米晶体大小是超级晶格形态和结合行为的一个关键决定因素.
- 取决于尺寸的双胞胎能量和粒子间潜能决定了自我组装的结果.
- 这项研究引入了一种新的多重生材料类别,具有针对定制的粒子间相互作用的潜力.
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