In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals.
Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. Here, we demonstrate the formation mechanism of 2D PbSe superstructures with square geometry by using in situ grazing-incidence X-ray scattering (small angle and wide angle), ex situ electron microscopy, and Monte Carlo simulations. We observed nanocrystal adsorption at the liquid/gas interface, followed by the formation of a hexagonal nanocrystal monolayer. The hexagonal geometry transforms gradually through a pseudo-hexagonal phase into a phase with square order, driven by attractive interactions between the {100} planes perpendicular to the liquid substrate, which maximize facet-to-facet overlap. The nanocrystals then attach atomically via a necking process, resulting in 2D square superlattices.
Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.|ID10, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France.
Jaco J
JJ
Geuchies
Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Carlo
C
van Overbeek
Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
Wiel H
WH
Evers
Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium.
Bart
B
Goris
Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium.
Annick
A
de Backer
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Anjan P
AP
Gantapara
Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Freddy T
FT
Rabouw
ID01, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France.
Jan
J
Hilhorst
Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Joep L
JL
Peters
ID10, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France.
Oleg
O
Konovalov
Physical and Colloidal Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TB Utrecht, The Netherlands.|Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
Andrei V
http://orcid.org/0000-0001-9840-6014
AV
Petukhov
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Marjolein
M
Dijkstra
Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands.
Laurens D A
LDA
Siebbeles
Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium.
Sandra
S
van Aert
Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium.
Sara
S
Bals
Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.
Daniel
D
Vanmaekelbergh