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A Technique to Functionalize and Self-assemble Macroscopic Nanoparticle-ligand Monolayer Films onto Template-free Substrates
Published on: May 9, 2014
Crystallinity segregation upon selective self-assembling of gold colloidal single nanocrystals.
Hervé Portalès1, Nicolas Goubet, Sergey Sirotkin
1Université Pierre et Marie Curie Paris 6, UMR 7070, LM2N, BP 52, 4 place Jussieu, 75005 Paris, France. herve.portales@upmc.fr
Nano Letters
|September 20, 2012
Summary
Single crystalline gold nanocrystals spontaneously segregate from polycrystalline ones in solution. This self-assembly into ordered superlattices simplifies nanocrystal control for applications.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Controlling nanocrystal (NC) crystallinity is crucial for optimizing their properties.
- Existing methods for crystallinity control are often complex and demanding.
Purpose of the Study:
- To investigate the spontaneous segregation of single crystalline from polycrystalline gold NCs.
- To understand the self-assembly behavior based on NC crystallinity.
Main Methods:
- Transmission electron microscopy (TEM) for size distribution analysis.
- Low-frequency Raman scattering and X-ray diffraction for nanocrystallinity characterization.
- Electron diffraction for analyzing NC self-assembly and ordering.
Main Results:
- Spontaneous segregation of single crystalline and polycrystalline 5 nm gold NCs observed in colloidal solution.
- Single crystalline NCs self-assemble into ordered superlattices at the air-solvent interface and in precipitates.
- Polycrystalline NCs remain dispersed in suspension without preferential orientation.
- No size segregation was observed between the different NC populations.
Conclusions:
- NC crystallinity, not size, dictates self-assembly behavior and segregation.
- The observed segregation offers a simple route to control NC crystallinity.
- This finding can optimize NC properties for various applications.
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