Direct Observation of Nanoparticle Superlattice Formation by Using Liquid Cell Transmission Electron Microscopy
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- 作者：Jungwon Park ; Haimei Zheng ; Won Chul Lee ; Phillip L. Geissler ; Eran Rabani ; A. Paul Alivisatos
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：March 27, 2012
- 年：2012
- 卷：6
- 期：3
- 页码：2078-2085
- 全文大小：497K
- 年卷期：v.6,no.3(March 27, 2012)
- ISSN：1936-086X
文摘
Direct imaging of nanoparticle solutions by liquid phase transmission electron microscopy has enabled unique in situ studies of nanoparticle motion and growth. In the present work, we report on real-time formation of two-dimensional nanoparticle arrays in the very low diffusive limit, where nanoparticles are mainly driven by capillary forces and solvent fluctuations. We find that superlattice formation appears to be segregated into multiple regimes. Initially, the solvent front drags the nanoparticles, condensing them into an amorphous agglomerate. Subsequently, the nanoparticle crystallization into an array is driven by local fluctuations. Following the crystallization event, superlattice growth can also occur via the addition of individual nanoparticles drawn from outlying regions by different solvent fronts. The dragging mechanism is consistent with simulations based on a coarse-grained lattice gas model at the same limit.