Yunmo Sung

Au- and Ag-ZnO composite nanocrystals having a dumbbell-like structure were successfully synthesized through the nucleation and decomposition of zinc hydroxide at the surface of pre-existing Au and Ag nanoparticles, respectively. The average size of the Au and Ag nanoparticles used was ∼4 nm and that of the ZnO nanocrystals was ∼10 nm. The composite nanocrystals show strong crystallinity of face-centered cubic and wurztite structures from Au or Ag and ZnO, respectively. The composite nanocrystal

Colloidal TiO 2 nanorods were synthesized with different aspect ratios and successfully doped with copper via a controlled hydrolysis method. Inductively coupled plasma (ICP) atomic emission spectroscopy analyses showed that the as-prepared TiO 2 nanorods contained ∼1.7−3.2 at% Cu. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses revealed that the doped nanorods are in a highly crystalline anatase structure and their crystal growth orientation is pref

Synthesis of TiO 2 nanowires directly on conductive and transparent glass substrates would be very useful for various applications such as photovoltaics and photocatalysis. Here, we report for the first time that single-crystalline TiO 2 nanowires can be synthesized on fluorine-doped tin oxide (SnO 2:F)-coated soda-lime glass substrates by chemical vapor deposition (CVD) at a temperature that is below the glass softening temperature (<530 °C). Moreover, we demonstrate that CdS nanorods with high

The growth mechanism of SnSe nanosheets synthesized by physical vapour deposition was elucidated in detail based upon crystal structure and surface energy.

Kinetic analysis on the nanocrystal solid-solution formation was performed by heat treating CdSe/ZnSe core/shell nanocrystals, synthesized via a typical TOP/TOPO approach, at different temperatures for different time periods. X-ray diffraction (XRD) peak shifts in Cd1-xZnxSe cores according to the solid-solution treatments were monitored and used for the estimation of the lattice parameter change. The degree of solid-solution formation was determined considering the compositional variation in Cd

Homogeneous mixtures of hydroxyapatite (HAp) and yttria-stabilized zirconia (YSZ) nanoparticles were successfully synthesized using chemical co-precipitation and subsequent calcination. For the synthesis of HAp/YSZ nanopowder, the Ca/P atomic ratio was 1.73 to obtain high-content stoichiometric hydroxyapatite phase and to suppress ?-tricalcium phosphate (?-TCP) formation. The agglomerated crystalline powders were milled using YSZ ball media to obtain well-separated nanoparticles. The final parti

High-density single-crystalline TiO 2 nanowires (∼50 nm diam) were successfully grown on Ti substrates by chemical vapor deposition at a low temperature of 700 °C and within a remarkably short time period of 5 min. They were combined with CdSe nanocrystals (∼5 nm diam) to form TiO 2 /CdSe heterotructured nanowires by overcoating the nanowires with the CdSe-containing solution and subsequent annealing at 600 °C. The TiO 2 /CdSe nanowires showed uniformly distributed CdSe nanocrystals, and high cr

Dramatic enhancements in the figure of merit have been obtained in bulk thermoelectric materials by doping, band engineering, and nanostructuring. Especially, in p-type thermoelectrics, high figure of merits near 2.0 have been reported in a few papers through the reduction in lattice thermal conductivity and the advancement in power factors. However, there exists no report on the n-type systems showing high figure of merits because of their intrinsically low Seebeck coefficients. Here, we demons

High-density and single-crystalline CdS nanowire arrays were formed on fluorine-doped tin oxide (FTO)-coated soda-lime glass substrates without aid of templates at 220 °C. Bi was employed as a catalyst for the low-temperature growth of CdS nanowires via solution−liquid−solid (SLS) mechanism. CdS nanowires were very straight and they were ∼20−50 nm in diameter and ∼2−3 μm in length. CdS nanowires were in highly crystalline wurtzite structure, and their crystal growth direction was [001]. Careful