In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals
Source abstract
Abstract
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.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Quantum Dots Synthesis And Properties · nanoparticles nucleation surface interactions · Copper-based nanomaterials and applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (36)
Show source-provided references
1. Evers, W. H. et al. Low-dimensional semiconductor superlattices formed by geometric control over nanocrystal attachment. Nano Lett. 13, 2317–2323 (2013).10.1021/nl303322k ↗
2. Boneschanscher, M. P. et al. Long-range orientation and atomic attachment of nanocrystals in 2D honeycomb superlattices. Science 344, 1377–1380 (2014).10.1126/science.1252642 ↗
3. Pound, G. M. & LaMer, V. K. Kinetics of crystalline nucleus formation in supercooled liquid Tin 1,2. J. Am. Chem. Soc. 74, 2323–2332 (1952).10.1021/ja01129a044 ↗
4. LaMer, V. K. & Dinegar, R. H. Theory, production and mechanism of formation of monodispersed hydrosols. J. Am. Chem. Soc. 72, 4847–4854 (1950).10.1021/ja01167a001 ↗
5. Banfield, J. F. Aggregation-based crystal growth and microstructure development in natural iron oxyhydroxide biomineralization products. Science 289, 751–754 (2000).10.1126/science.289.5480.751 ↗
6. Pacholski, C., Kornowski, A. & Weller, H. Self-assembly of ZnO: from nanodots to nanorods. Angew. Chem. Int. Ed. Engl. 41, 1188–1191 (2002).10.1002/1521-3773(20020402)41:7<1188::AID-ANIE1188>3.0.CO;2-5 ↗
7. Li, D. et al. Direction-specific interactions control crystal growth by oriented attachment. Science 336, 1014–1018 (2012).10.1126/science.1219643 ↗
8. Schliehe, C. et al. Ultrathin PbS sheets by two-dimensional oriented attachment. Science 329, 550–553 (2010).10.1126/science.1188035 ↗
9. Cho, K.-S., Talapin, D. V., Gaschler, W. & Murray, C. B. Designing PbSe nanowires and nanorings through oriented attachment of nanoparticles. J. Am. Chem. Soc. 127, 7140–7147 (2005).10.1021/ja050107s ↗
10. Kalesaki, E., Evers, W. H., Allan, G., Vanmaekelbergh, D. & Delerue, C. Electronic structure of atomically coherent square semiconductor superlattices with dimensionality below two. Phys. Rev. B 88, 115431 (2013).10.1103/PhysRevB.88.115431 ↗
11. Kalesaki, E. et al. Dirac cones, topological edge states, and nontrivial flat bands in two-dimensional semiconductors with a honeycomb nanogeometry. Phys. Rev. X 4, 011010 (2014).
12. Beugeling, W. et al. Topological states in multi-orbital HgTe honeycomb lattices. Nat. Commun. 6, 6316 (2015).10.1038/ncomms7316 ↗
13. Evers, W. H. et al. High charge mobility in two-dimensional percolative networks of PbSe quantum dots connected by atomic bonds. Nat. Commun. 6, 8195 (2015).10.1038/ncomms9195 ↗
14. Whitham, K. et al. Charge transport and localization in atomically coherent quantum dot solids. Nat. Mater. 15, 557–563 (2016).10.1038/nmat4576 ↗
15. Pietra, F. et al. Semiconductor nanorod self-assembly at the liquid/air interface studied by in situ GISAXS and ex situ TEM. Nano Lett. 12, 5515–5523 (2012).10.1021/nl302360u ↗
16. Bian, K. et al. Shape-anisotropy driven symmetry transformations in nanocrystal superlattice polymorphs. ACS Nano 5, 2815–2823 (2011).10.1021/nn103303q ↗
17. Li, R., Bian, K., Hanrath, T., Bassett, W. A. & Wang, Z. Decoding the superlattice and interface structure of truncate PbS nanocrystal-assembled supercrystal and associated interaction forces. J. Am. Chem. Soc. 136, 12047–12055 (2014).10.1021/ja5057032 ↗
18. Choi, J. J. et al. Controlling nanocrystal superlattice symmetry and shape-anisotropic interactions through variable ligand surface coverage. J. Am. Chem. Soc. 133, 3131–3138 (2011).10.1021/ja110454b ↗
19. Choi, J. J., Bian, K., Baumgardner, W. J., Smilgies, D.-M. & Hanrath, T. Interface-induced nucleation, orientational alignment and symmetry transformations in nanocube superlattices. Nano Lett. 12, 4791–4798 (2012).10.1021/nl3026289 ↗
20. Weidman, M. C., Smilgies, D.-M. & Tisdale, W. A. Kinetics of the self-assembly of nanocrystal superlattices measured by real-time in situ X-ray scattering. Nat. Mater. 15, 775–781 (2016).10.1038/nmat4600 ↗
21. Evers, W. H. et al. Entropy-driven formation of binary semiconductor-nanocrystal superlattices. Nano Lett. 10, 4235–4241 (2010).10.1021/nl102705p ↗
22. Bodnarchuk, M. I., Kovalenko, M. V., Heiss, W. & Talapin, D. V. Energetic and entropic contributions to self-assembly of binary nanocrystal superlattices: temperature as the structure-directing factor. J. Am. Chem. Soc. 132, 11967–11977 (2010).10.1021/ja103083q ↗
23. Hanrath, T., Choi, J. J. & Smilgies, D.-M. Structure/processing relationships of highly ordered lead salt nanocrystal superlattices. ACS Nano 3, 2975–2988 (2009).10.1021/nn901008r ↗
24. Narayanan, S., Wang, J. & Lin, X.-M. Dynamical self-assembly of nanocrystal superlattices during colloidal droplet evaporation by in situ small angle x-ray scattering. Phys. Rev. Lett. 93, 135503 (2004).10.1103/PhysRevLett.93.135503 ↗
25. Simon, P. et al. Interconnection of nanoparticles within 2D superlattices of PbS/oleic acid thin films. Adv. Mater. 26, 3042–3049 (2014).10.1002/adma.201305667 ↗
26. Van Aert, S., Batenburg, K. J., Rossell, M. D., Erni, R. & Van Tendeloo, G. Three-dimensional atomic imaging of crystalline nanoparticles. Nature 470, 374–377 (2011).10.1038/nature09741 ↗
27. Van Aert, S. et al. Procedure to count atoms with trustworthy single-atom sensitivity. Phys. Rev. B 87, 064107 (2013).10.1103/PhysRevB.87.064107 ↗
28. Jones, L., MacArthur, K. E., Fauske, V. T., van Helvoort, A. T. J. & Nellist, P. D. Rapid estimation of catalyst nanoparticle morphology and atomic-coordination by high-resolution Z-contrast electron microscopy. Nano Lett. 14, 6336–6341 (2014).10.1021/nl502762m ↗
29. Bals, S. et al. Atomic scale dynamics of ultrasmall germanium clusters. Nat. Commun. 3, 897 (2012).10.1038/ncomms1887 ↗
30. Woo, J. Y. et al. Ultrastable PbSe nanocrystal quantum dots via in situ formation of atomically thin halide adlayers on PbSe(100). J. Am. Chem. Soc. 136, 8883–8886 (2014).10.1021/ja503957r ↗
31. Thapar, V. et al. Entropic self-assembly of freely rotating polyhedral particles confined to a flat interface. Soft Matter 11, 1481–1491 (2015).10.1039/C4SM02641A ↗
32. Sandeep, C. S. S. et al. Epitaxially connected PbSe quantum-dot films: controlled neck formation and optoelectronic properties. ACS Nano 8, 11499–11511 (2014).10.1021/nn504679k ↗
33. Baumgardner, W. J., Whitham, K. & Hanrath, T. Confined-but-connected quantum solids via controlled ligand displacement. Nano Lett. 13, 3225–3231 (2013).10.1021/nl401298s ↗
34. Zhang, H., De Yoreo, J. J. & Banfield, J. F. A unified description of attachment-based crystal growth. ACS Nano 8, 6526–6530 (2014).10.1021/nn503145w ↗
35. Zhang, H. & Banfield, J. F. Energy calculations predict nanoparticle attachment orientations and asymmetric crystal formation. J. Phys. Chem. Lett. 3, 2882–2886 (2012).10.1021/jz301161j ↗
36. Steckel, J. S., Yen, B. K. H., Oertel, D. C. & Bawendi, M. G. On the mechanism of lead chalcogenide nanocrystal formation. J. Am. Chem. Soc. 128, 13032–13033 (2006).10.1021/ja062626g ↗