1. In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals
- Author
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Geuchies, J.J., van Overbeek, C., Evers, W.H., Goris, Bart, de Backer, Annick, Gantapara, A.P., Rabouw, F.T., Hilhorst, J., Peters, J.L., Konovalov, Oleg, Petukhov, Andrei V., Dijkstra, M., Siebbeles, Laurens D A, Van Aert, S., Bals, Sara, Vanmaekelbergh, D.A.M., Condensed Matter and Interfaces, Soft Condensed Matter and Biophysics, Physical and Colloid Chemistry, Sub Condensed Matter and Interfaces, Sub Soft Condensed Matter, Sub Physical and Colloid Chemistry, Physical Chemistry, Condensed Matter and Interfaces, Soft Condensed Matter and Biophysics, Physical and Colloid Chemistry, Sub Condensed Matter and Interfaces, Sub Soft Condensed Matter, and Sub Physical and Colloid Chemistry
- Subjects
Materials science ,Superlattice ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,01 natural sciences ,Condensed Matter::Materials Science ,Phase (matter) ,Monolayer ,Taverne ,General Materials Science ,Scattering ,Mechanical Engineering ,Physics ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Crystallography ,Chemistry ,Nanocrystal ,Mechanics of Materials ,Chemical physics ,Quantum dot ,Self-assembly ,0210 nano-technology - Abstract
Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order1, 2. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals3, 4, 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.
- Published
- 2016