Seeded growth of asymmetric binary nanocrystals made of a semiconductor TiO2 rodlike section and a magnetic gamma-Fe2O3 spherical domain.
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.
Buonsanti
Raffaella
R
Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy.
Grillo
Vincenzo
V
Carlino
Elvio
E
Giannini
Cinzia
C
Curri
Maria Lucia
ML
Innocenti
Claudia
C
Sangregorio
Claudio
C
Achterhold
Klaus
K
Parak
Fritz Günter
FG
Agostiano
Angela
A
Cozzoli
Pantaleo Davide
PD
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
D005290:Ferric Compounds; D058085:Iron Compounds; C009495:titanium dioxide; C000499:ferric oxide; D014025:Titanium