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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Shape-anisotropy driven symmetry transformations in nanocrystal superlattice polymorphs.
Kaifu Bian1, Joshua J Choi, Ananth Kaushik
1School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA.
ACS Nano
|February 25, 2011
Summary
Controlling nanocrystal superlattice (NCSL) symmetry is key to unlocking their potential. This study demonstrates solvent vapor control over NCSL symmetry, enabling tunable material properties for advanced applications.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Physics
Background:
- Nanocrystal superlattices (NCSLs) offer unique properties but lack synthetic control.
- Understanding molecular interactions is crucial for realizing NCSL potential.
- Limited control over superlattice spacing and symmetry hinders technological development.
Purpose of the Study:
- To demonstrate control over NCSL symmetry through molecular interactions.
- To investigate solvent vapor-mediated symmetry transformations.
- To provide insights into the physics governing NCSL assembly.
Main Methods:
- In situ grazing incidence small-angle X-ray scattering (GISAXS) to study real-time assembly.
- Controlled solvent vapor exposure to induce symmetry changes.
- All-atom molecular dynamics simulations for theoretical validation.
Main Results:
- Demonstrated solvent vapor-mediated control over NCSL symmetry.
- Observed transformations into various superlattice polymorphs (fcc, bcc, bct).
- Gained quantitative insights into solvent-ligand interactions and assembly dynamics.
Conclusions:
- NCSL symmetry can be precisely controlled by manipulating ligand-solvent interactions.
- This approach enables the rational design of NCSLs with desired properties.
- The findings pave the way for developing novel NCSL-based materials and technologies.
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