Nanocrystal superlattices

Flarfenist S A and Wang Z L 1999 Fligh-temperature stability of passivated silver nanocrystal superlattices J. Phys. Chem. B 103 4342... 

Figure 9. TEM micrographs of nanocrystal superlattices of Au nanoparticles prepared by the inverse micelle method and digestive ripening, (a) and (b) low-magnification images (c (f) regularly-shaped nanocrystal superlattices (g) magnified image of a superlattice edge. Note the perfect arrangement of the Au nanoparticles. (Reprinted with permission from Ref. [30], 2003, American Chemical Society.)...

Lin, X.M., Jaeger, H.M., Sorensen, C.M. and Klabunde, K.J. (2001) Formation of long-range-ordered nanocrystal superlattices on silicon nitride substrates. Journal of Physical Chemistry B, 105 (17), 3353-3357. 

Sun, S. Murray, C. B. Weller, D. Folks, L. Moser, A. 2000. Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science 287 1989-1992. 

Urban, J. J. Talapin, D. V. Shevchenko, E. V. Murray, C. B. 2006. Self-assembly of PbTe quantum dots into nanocrystal superlattices and glassy films. J. Am. Chem. Soc. 128 3248-3255. 

Black C. T., Murray C. B., Sandstrom R. L. and Sun S., Spin-dependent tunneling in self-assembled cobalt-nanocrystal superlattices. Science 290 (2000) pp. 1131-1134. 

Collier CP, Vossmeyer T, Heath JR (1998) Nanocrystal superlattices. Ann Rev Phys Chem 49 371-404 Cordfrtrrke EHP, Korrings RJM (1990) Thermochemical Data for Reactor Materials and Fission Products. North-Holland, Amsterdam. 

Coimolly S, Fullam S, Korgel B, Fitzmaurice D (1998) Time-resolved small-angle X-ray scattering studies of nanocrystal superlattice self-assembly. J Am Chem Soc 120 2969-2970 deGroot F (2001) High-resolution X-ray emission and X-ray absorption spectroscopy. Chem Rev 101 1779-1808... 

Sigman MB, Saunders AE, Korgel BA (2004) Metal nanocrystal superlattice nucleation and growth. Langmuir 20(3) 978-983... 

G. Schmid, M. Baumle, and N. Beyer, Ordered two-dimensional monolayers of AU53 clusters, Angew. Chem. Int. Ed. 39 181 (2000) S. Chen, Two-dimensional crosslinked nanoparticle networks, Ac v. Mater. 12 186 (2000) S. Sun, C.B. Murray, D. Weller, L. Folks, and A. Moser, Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science 287 1989 (2000) C.L. Bowes and G.A. Ozin, Self-assembling frameworks beyond microporous oxides, Adv. Mater. 8 13 (1996). 

Yet another development of remarkable nanostmctured materials yields superlattices of nanosized objects. As there is no dear distinction between molecular crystals and superlattices formed from nanopartides, at this point reference will be made to structures composed of very similar (but most likely not exactly identical) nanopartides, namely colloidal partides in the size range 2 to 10 nm. Two excellent reviews by leading experts in the field were produced in 1998 and 2000 [19, 20], the titles of which contained the terms nanocrystal superlattices and close-packed nanociystal assemblies. These are in line with the above-outlined delimitation, although Collier et al. have also reported on molecular crystals (as above). The two reviews comprised approximately 100 pages with some 300 references, and summarized the state of the art at that time in exemplary fashion. The topics induded preparative aspects of the formation of monodisperse nanopartides of various compositions including metals, the superlattice formation itself with some theoretical background, covalent linking of nanocrystals (see below), and an appropriate description of the physical properties and characterization of the nanocrystal superlattices. 

Figure 4.1 (a) Schematic illustration of superlattice formation from colloidal solutions of 3.5 nm CdSe nanocrystals in toluene (b,c) Optical micrographs of the evolving nanocrystal superlattices after fast (b) and slow (c) nucleation. Reproduced with permission from Ref [24],... 

Based on studies of the formation of amorphous 3-D arrays of CdSe nanocrystals [44] and of compact round disks of similar particles [45], a step forward was proposed by Ge and Brus, who reported planar monolayer aggregates that consisted of 80-100 identical 4 nm CdSe nanocrystals which diffused on planar graphite surfaces [46]. Subsequent investigations into the collective motion of a very small nanocrystal superlattice have opened up yet another new field of research. 

X. M. Lin, C. M. Sorensen and K. J. Klabunde, Ligand-induced gold nanocrystal superlattice... 

FIGURE 6.10 Synthetic steps for preparation of nanocrystal superlattice and TEM image of thus obtained gold nanoparticle (adapted from Reference 160 with permission). 

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