对二元纳米晶超级网的自我组装的能量和热贡献:温度作为结构指导因素
Maryna I Bodnarchuk1, Maksym V Kovalenko, Wolfgang Heiss
1Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|August 13, 2010
概括
温度控制纳米晶体超级的自我组装. 通过调整温度,研究人员可以量身定制粒子间相互作用和来指导各种二进制超级晶格结构的形成,从而影响它们的密度和复杂性.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术 纳米技术
- 物理化学 物理化学
背景情况:
- 合性纳米晶体自组装成有序的超级格子.
- 温度影响热力学贡献 (能量和) 自组装.
- 了解温度效应对于控制超级格子结构至关重要.
研究的目的:
- 调查温度对纳米晶体自组装成超级晶格的影响.
- 确定温度如何影响单元和二元超级网格的形成.
- 探索温度在指导纳米晶体超级的结构多样性的作用.
主要方法:
- 研究了单分散的合性纳米晶体 (CdSe,PbS,PbSe,Pd) 的自我组装.
- 变化的温度作为影响赫尔姆霍尔茨自由能量 (F = U - TS) 的关键参数.
- 分析了由此产生的超级网格结构,包括密度和相位图.
主要成果:
- 温度显著影响二进制超级网格结构 (CdSe + PbS和PbSe + Pd).
- 由于小的哈马克尔常数,CdSe + PbS混合物形成了简单的,高密度的超级格子.
- PbSe + Pd混合物表现出复杂的低密度相,在不同温度下通过范德瓦尔斯相互作用稳定.
结论:
- 纳米粒子超级网的结构多样性源于由驱动的结晶和粒子间相互作用.
- 内能 (Delta U) 和 (T Delta S) 的相对贡献决定了超级网格的形成.
- 温度是调整能量和之间的平衡以实现所需的超级晶格结构的关键因素.
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