Polymorphism in nanoparticle-based crystals depending upon their single or polycrystalline character. Issue 33 (30th June 2016)

• Record Type: Journal Article
• Authors: Goubet, N.; Albouy, P. A.; Thompson, A.; Pileni, M. P.
• Is Part Of: CrystEngComm. Volume 18:Issue 33(2016)
• Page Start: 6166
• Page End: 6175
• Publication Date: 2016-06-30
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c6ce01006g
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : Crystal defects of gold nanocrystals induce polymorphism in their corresponding colloidal crystals. Single colloidal crystal diffraction investigation has shown that packing of single crystals (5 nm) leads to a body-centered cubic lattice with orientational order, whereas gold polycrystalline nanoparticles self-assemble into a face-centered cubic lattice. Abstract : Colloidal single crystals of submillimeter size (colloidal crystal) are built by self-assembly of gold nanoparticles with nearly similar size ( ca. 5 nm) but different nanocrystallinities. The external shape of the gold nanoparticles was characterized using electron microscopy and related to their nanocrystallinity. A synchrotron-based experiment is used to collect X-ray diffraction patterns from individual single crystals over the wide q -range relevant to both interatomic and interparticle periodicities. This makes possible a detailed reconstruction of the reciprocal space including diffuse scattering. X-ray diffraction demonstrates that colloidal crystals made up of single-crystal nanoparticles belong to the body-centered cubic system while face-centered cubic single crystals are observed in the case of self-assembly by polycrystalline particles. A remarkable feature is the preferential orientation of the symmetry axes of the single-crystal nanoparticles along those of the colloidal crystal; on the contrary, polycrystalline nanoparticles display random orientation. These results show the importance of the nanocrystallinity for the packing behavior.