High-Pressure Structural Stability and Elasticity of Supercrystals Self-Assembled from Nanocrystals.
In: Nano Letters, Jg. 11 (2011-02-09), Heft 2, S. 579-588
Online
academicJournal
Zugriff:
We report here combined quasi-hydrostatic high-pressure small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD) studies on faceted 3D supercrystals (SCs) self-assembled from colloidal 7.0 nm spherical PbS nanocrystals (NCs). Diamond anvil cell (DAC) SAXS experiments in the pressure range from ambient to 12.5 GPa revealed nearly perfect structural stability of the SCs, with face-centered cubic organization of the NCs. Pressure-induced ordering (annealing effect) of the superstructure was observed. The ambient pressure bulk modulus of the SCs was calculated to be â¼5 GPa for compression and â¼14.5 GPa for decompression from fitting of Vinet and BirchâMurnaghan equations of state. XRD measurements revealed strong preferential crystallographic orientation of the NCs through all phase transformations to as high as 55 GPa without any indication of NC sintering. The first phase transition pressure of the NCs was found between 8.1 and 9.2 GPa and proceeds through homogeneous nucleation. Bulk modulus of PbS NCs was calculated to be â¼51 GPa based on fitting to the equations of state (KPbS,bulkâ¼ 51â57 GPa). Closest surface-to-surface distance between the NCs in the SCs was calculated based on combined XRD and SAXS data, to reversibly tune from â¼1.56 nm to â¼0.9â0.92 nm and back to â¼1.36 nm in the ambientâ12.5 GPaâambient pressure cycle. The bulk modulus of the ligand matrix was extrapolated to be â¼2.2â2.95 GPa. These results show a general method of tuning NC interactions in packed nanoparticle solids. [ABSTRACT FROM AUTHOR]
Titel: |
High-Pressure Structural Stability and Elasticity of Supercrystals Self-Assembled from Nanocrystals.
|
---|---|
Autor/in / Beteiligte Person: | Podsiadlo, Paul ; Lee, Byeongdu ; Prakapenka, Vitali B. ; Krylova, Galyna V. ; Schaller, Richard D. ; DemortieÌre, Arnaud ; Shevchenko, Elena V. |
Link: | |
Zeitschrift: | Nano Letters, Jg. 11 (2011-02-09), Heft 2, S. 579-588 |
Veröffentlichung: | 2011 |
Medientyp: | academicJournal |
ISSN: | 1530-6984 (print) |
DOI: | 10.1021/nl103587u |
Schlagwort: |
|
Sonstiges: |
|