title: Seeded growth of asymmetric binary nanocrystals made of a semiconductor TiO2 rodlike section and a magnetic gamma-Fe2O3 spherical domain.
abstract: Asymmetric binary nanocrystals (BNCs), comprising one c-axis elongated anatase TiO2 section and one gamma-Fe2O3 spherical domain attached together, are synthesized by heterogeneous nucleation of iron oxide onto the longitudinal facets of TiO2 nanorods in a ternary surfactant mixture. The topologically controlled composition of the BNCs is ascertained by a combination of powder X-ray diffraction, Raman and Mössbauer spectroscopy, high-angle annular dark-field imaging, and high-resolution transmission electron microscopy lattice fringe mapping, while their size-dependent magnetic behavior is demonstrated by ac susceptibility measurements. The heteroepitaxial growth proceeds through a mechanism never observed before for colloidal nanoheterostructures: the two domains share a restricted and locally curved junction region, which accommodates efficiently the interfacial strain and retards the formation of misfit dislocations. It is believed that these BNCs, which combine the properties of two technologically relevant oxide materials, can pave the way to reinforced applications in several fields of nanoscience, such as in photocatalysis, in malignant cell treatments, and in nanocrystal assembly.
authors.affiliation: Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Buonsanti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Grillo
authors.forename: Elvio
authors.initials: E
authors.lastname: Carlino
authors.forename: Cinzia
authors.initials: C
authors.lastname: Giannini
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Curri
authors.forename: Claudia
authors.initials: C
authors.lastname: Innocenti
authors.forename: Claudio
authors.initials: C
authors.lastname: Sangregorio
authors.forename: Klaus
authors.initials: K
authors.lastname: Achterhold
authors.forename: Fritz Günter
authors.initials: FG
authors.lastname: Parak
authors.forename: Angela
authors.initials: A
authors.lastname: Agostiano
authors.forename: Pantaleo Davide
authors.initials: PD
authors.lastname: Cozzoli
mesh_terms: D003460:Crystallization; D005290:Ferric Compounds / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D012666:Semiconductors; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; C009495:titanium dioxide; C000499:ferric oxide; D014025:Titanium