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Abstract: A simple approach based on an organically modified sol–gel process has been developed to fabricate PbTiO3 (PT) nanocrystals on Si (100) substrate, where the amorphous powder modified by acetylacetone (acac) was used as precursor. After dropping the amorphous powder precursor prepared by freeze-drying process, PT nanocrystals on Si (100) substrate were obtained after heat treatment at 720°C for 30min in air. PT nanocrystals have been detected by XRD to be tetragonal perovskite structure. With the increase of acac/Pb molar ratio, the relative (100)/(001) diffraction peak intensity gradually increases, which probably suggested an oriented growth of PT nanocrystal along [100] on Si (100) substrates. In addition, Atomic force microscopy (AFM) results indicated that the height and the average lateral size of PT nanocrystal increased and then decreased as the acac/Pb molar ratio increased. Piezoelectric force microscopy (PFM) results demonstrated that all the samples show obvious piezoelectric activity. These results implied that the acetylacetone molecular mediated the growth of PT nanocrystals on Si (100) substrates possibly by the acac/Pb molar ratio. This simple method has been suggested to be attractive for tailoring an oriented growth of the nanostructures of perovskite oxide systems on Si substrates. [Copyright &y& Elsevier]

Abstract: Ring- and single-crystal-like superstructures of Fe-doped PbTiO3 nanocrystals have been prepared by a simple hydrothermal method using (poly ethylene glycol) (PEG) as a surfactant. Two oriented-attachment forms of the nanocrystals favor the formation of the rings in view of geometry. Magnetism measurement shows that Fe-doped PbTiO3 sample is ferromagnetic even at room temperature. It is proposed that the magnetic dipole interactions and the presence of PEG molecules could together contribute to the formation of ring- and single-crystal-like superstructures composed of Fe-doped PbTiO3 nanocrystals. [Copyright &y& Elsevier]

Abstract: Single-crystal SrTiO3 dendritic nanostructures were synthesized for the first time via a simple hydrothermal method without any surfactant. Structure characterizations suggest that the SrTiO3 dendrites show preferential orientation along [110]. Additionally, it is found that KOH concentration plays an important role in the formation of SrTiO3 dendrites, and the morphology of SrTiO3 crystallites can vary from cubic-like, star-like to dendritic shape. A rational mechanism is proposed to illustrate the growth of SrTiO3 dendrites. [Copyright &y& Elsevier]

A new method has been developed to synthesize barium titanate (BaTiO3) nanoparticles with a narrow size distribution under ambient conditions at room temperature. The as-prepared BaTiO3 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, high-resolution TEM, and selected area electron diffraction. On the basis of the characterizations, it was found that the particle size could be easily tuned by adjusting the experimental parameters, such as the solvent component and reaction time. The basicity of the organic solvent was considered to play an important role in the room-temperature synthesis and the solvent molecules had a strong influence on the crystal growth of BaTiO3 nanoparticles. The BaTiO3 nanoparticles obtained were well dispersed and possessed a cubic perovskite structure at room temperature. [ABSTRACT FROM AUTHOR]