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A novel procedure to fabricate nanoarchitectures of crystalline titania hollow shells was developed by using assembled latex particles as templates. Latex particles were assembled on the surface of solid substrates and covered with ultrathin titania films by the surface sol–gel process. When the titania-covered latex particle was subjected to oxygen plasma treatment, hollow titania spheres were formed at the original site of particle deposition. Following calcination of the amorphous, titania hollow shells induced their crystallization to titania nanocrystals (anatase).

Monodispersed DAST nanocrystals have almost been successfully fabricated by means of the inverse reprecipitation method. By employing AC electric field, high electric field of above ca. 1.0 kVcm^-1 could be applied to polar DAST nanocrystals dispersed in decahydronaphthalene, so as to avoid electrophoresis of nanocrystals under DC electric field. The response of DAST nanocrystal dispersion to applied AC electric field was analyzed phenomenologically by fitting Langevin function, which provided a large permanent dipole moment of DAST nanocrystal. In addition, we have succeeded in in situ observation of AC electric-field-induced orientational motion of DAST crystals by using an optical microscope. The present DAST nanocrystal dispersion system will be expected as an optical device like display monitor.

Photoluminescent properties of CdSe/ZnS nanocrystals (quantum dots, QDs) in complexes with elongated gold nanoparticles was found to be dependent on the effective refractive index of the medium. It has been experimentally shown that changes in the refractive index make possible to increase the photoluminescence intensity by several times.

A series of cadmium telluride (CdTe) nanocrystals were synthesized by a modified organometallic synthesis method at various reaction temperatures ranging from 130 to 250°C. In this method, octadecylamine (ODA) was introduced as an additional coordinating component to the mixture of trioctylphosphine oxide (TOPO) and trioctylphosphine (TOP). CdO was used as a precursor. The prepared CdTe nanocrystals were studied by the absorption and emission spectra as well as the powder X-ray diffraction (XRD) patterns. The result shows that besides the traditional continuous-growth mode observed frequently at relatively high reaction temperature, a discontinuous-growth mode was confirmed at the initial growth stage of CdTe nanocrystals, arising from the change of the absorption spectra of CdTe nanocrystals with the reaction time at relatively low reaction temperature. The structures of CdTe nanocrystals, e.g., the cubic zinc blende structure at 160°C and the hexagonal wurtzite structure at 250°C, were characterized by XRD.

Colloidal CdSe nanocrystals (NCs) were etched after Se/TBP and Zinc stearate/ODE were injected into the mixture of as-prepared CdSe NCs and Copper (II) acetate in ODE solvent. Spectroscopic and structural investigations demonstrate the etching process. Along with the etching time, both the absorption and photoluminescence (PL) spectra of etched NCs showed blue-shift while the transmission electron microscopy (TEM) images indicated that the size of the NCs became from 5.6nm to 2.6nm. X-ray diffraction (XRD) patterns suggested that no other clusters or core/shell NCs were formed in the etching process and inductively coupled plasma (ICP) data demonstrated that only selenium and cadmium comprised the etched NCs. Electronic paramagnetic resonance (EPR) spectra indicated the deoxidization of Cu${}^{2+}$ ions and suggested the etching mechanism through cation exchange process.

The technology progress and increasing high density demand have driven the nonvolatile memory devices into nanometer scale region. There is an urgent need of new materials to address the high programming voltage and current leakage problems in the current flash memory devices. As one of the most important nanomaterials with excellent mechanical and electronic properties, carbon nanotube has been explored for various nonvolatile memory applications. While earlier proposals of “bucky shuttle” memories and nanoelectromechanical memories remain as concepts due to fabrication difficulty, recent studies have experimentally demonstrated various prototypes of nonvolatile memory cells based on nanotube field-effect-transistor and discrete charge storage bits, which include nano-floating gate memory cells using metal nanocrystals, oxide-nitride-oxide memory stack, and more simpler trap-in-oxide memory devices. Despite of the very limited research results, distinct advantages of high charging efficiency at low operation voltage has been demonstrated. Single-electron charging effect has been observed in the nanotube memory device with quantum dot floating gates. The good memory performance even with primitive memory cells is attributed to the excellent electrostatic coupling of the unique one-dimensional nanotube channel with the floating gate and the control gate, which gives extraordinary charge sensibility and high current injection efficiency. Further improvement is expected on the retention time at room temperature and programming speed if the most advanced fabrication technology were used to make the nanotube based memory cells.