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Lokteva I, Koof M, Walther M, Grübel G, Lehmkühler F. Coexistence of hcp and bct Phases during In Situ Superlattice Assembly from Faceted Colloidal Nanocrystals. J Phys Chem Lett 2019; 10:6331-6338. [PMID: 31578064 DOI: 10.1021/acs.jpclett.9b02622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We study the in situ self-assembly of faceted PbS nanocrystals from colloidal suspensions upon controlled solvent evaporation using time-resolved small-angle X-ray scattering and X-ray cross-correlation analysis. In our bulk-sensitive experiment in transmission geometry, the superlattice crystallization is observed in real time, revealing a hexagonal closed-packed (hcp) structure followed by formation of a body-centered cubic (bcc) superlattice. The bcc superlattice undergoes continuous tetragonal distortion in the solvated state shortly after its formation, resulting in the body-centered tetragonal (bct) structure. Upon solvent evaporation, the bct superstructure becomes more pronounced with the still coexisting hcp phase. These findings corroborate the existing simulations of assembling cuboctahedral-shaped particles and illustrate that we observed the predicted equilibrium states. This work is essential for a deeper understanding of the fundamental forces that direct nanocrystal assembly including nanocrystal shape and ligand coverage.
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Affiliation(s)
- Irina Lokteva
- Deutsches Elektronen-Synchrotron (DESY) , Notkestraße 85 , 22607 Hamburg , Germany
- The Hamburg Centre for Ultrafast Imaging (CUI) , Luruper Chaussee 149 , 22761 Hamburg , Germany
| | - Michael Koof
- Deutsches Elektronen-Synchrotron (DESY) , Notkestraße 85 , 22607 Hamburg , Germany
- The Hamburg Centre for Ultrafast Imaging (CUI) , Luruper Chaussee 149 , 22761 Hamburg , Germany
| | - Michael Walther
- Deutsches Elektronen-Synchrotron (DESY) , Notkestraße 85 , 22607 Hamburg , Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron (DESY) , Notkestraße 85 , 22607 Hamburg , Germany
- The Hamburg Centre for Ultrafast Imaging (CUI) , Luruper Chaussee 149 , 22761 Hamburg , Germany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron (DESY) , Notkestraße 85 , 22607 Hamburg , Germany
- The Hamburg Centre for Ultrafast Imaging (CUI) , Luruper Chaussee 149 , 22761 Hamburg , Germany
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Lehmkühler F, Schroer MA, Markmann V, Frenzel L, Möller J, Lange H, Grübel G, Schulz F. Kinetics of pressure-induced nanocrystal superlattice formation. Phys Chem Chem Phys 2019; 21:21349-21354. [PMID: 31531471 DOI: 10.1039/c9cp04658e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Colloidal nanocrystals (NC) are known to self-organize into superlattices that promise many applications ranging from medicine to optoelectronics. Recently, the formation of high-quality PEGylated gold NC was reported at high hydrostatic pressure and high salt concentrations. Here, we study the formation kinetics of these superlattices after pressure jumps beyond their crystallisation pressure by means of small-angle X-ray scattering with few ms experimental resolution. The timescale of NC formation was found to be reduced the larger the width of the pressure jump. This is connected to an increase of crystal quality, i.e., the faster the NC superlattice forms, the better the crystal quality. In contrast to the formation kinetics, the melting of the NC superlattice is approximately one order of magnitude slower and shows linear kinetics.
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Affiliation(s)
- Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany. and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Martin A Schroer
- European Molecular Biology Laboratory EMBL c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Verena Markmann
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
| | - Lara Frenzel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany. and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | - Holger Lange
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany and Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany. and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Florian Schulz
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany and Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
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