Researchers at the University of Chicago Materials Research Science and Engineering Center carried out the first systematic study of structural defects in binary nanocrystal superlattices (BNSLs). This work has demonstrated that many structural defects existing in atomic solids can be also observed in BNSLs. In addition, new types of structural defects emerge due to finite size variation of BNSL building blocks. The ability to observe these defects in real-space using electron microscopy offers exiting opportunities for detailed structural analysis of defects in complex binary lattices. Such direct observation of local imperfections in complex multicomponent lattices provides a unique insight at the fundamental aspects of crystal formation. As an example, it allowed the first reconstruction of an epitaxial interface between crystalline and quasicrystalline lattices (see Figure ).
TEM image of the interface between dodecagonal quasicrystal and CaB6-type Binary NanocrystalSuperlattices. The inset shows the structural defect (“misfit” dislocation) typical for the interface between crystalline and quasicrystalline phases.
M. I. Bodnarchuk, E. V. Shevchenko, D. V. Talapin. J. Am. Chem. Soc, 133, 20837–20849 (2011). DOI: 10.1021/ja207154v