Room-Temperature Homogeneous Nucleation Synthesis and Thermal Stability of Nanometer Single Crystal CeO₂

Nanometer (about 4~5nm) CeO2 single crystals were first synthesized by room-temperature homogeneous nucleation; the size was determined by electron microscopy and specific surfaced area of the particles. Modeling revealed that the surface energy of as-synthesized nanometer single crystals was in the range of 2.8-3.7J/m2. Crystal growth mechanisms change over the temperature regimes, from boundary diffusion over low-temperature regime (Eα=0.16eV) to bulk diffusion (Eα=0.50eV) over high-temperature region

Method for Preparation of Nanometer Cerium-Based Oxide Particles

The invention comprises novel undoped and doped nanometer-scale CeO2 particles as well as a novel semi-batch reactor method for directly synthesizing the novel particles at room temperature. The powders exhibited a surface area of approximately 170 m2/g with a particle size of about 3-5 nm, and are formed of single crystal particles that are of uniform size and shape. The particles’ surface area could be decreased down to 5 m2/g, which corresponds to a particle size of 100 nm, by thermal annealing at temperatures up to 1000° C. Control over the particle size, size distribution and state of agglomeration could be achieved through variation of the mixing conditions such as the feeding method, stirrer rate, amount of O2 gas that is bubbled through the reactor, the temperature the reaction is carried out at, as well as heating the final product at temperatures ranging from 150° to 1000° C

Method for Fabricating Nanostructured Solid Oxide Fuel Cells and Cell Components

A method of fabricating a nanostructured solid oxide fuel cell includes dispersing ceria and doped ceria nanoparticles in a first colloidal solution, atomizing the first colloidal solution into a spray, depositing the spray onto a substrate to form a thin film electrolyte, dispersing a nanocomposite powder including ceria and CuO in the first solution, forming a second colloidal solution, atomizing the second colloidal solution into a second spray, and depositing the second spray over the thin film electrolyte as an interfacial layer

Novel Yttrium-Stabilized Zirconia Polymeric Precursor for the Fabrication of Thin Films

An acetate-based polymeric precursor for producing yttrium-stabilized zirconia (YSZ) was developed. The precursor was prepared under ambient conditions and contains only yttrium and zirconium cations. Dense, crack-free films were fabricated with this precursor on alumina substrates at a rate of 60 nm per deposition, producing polycrystalline YSZ at temperatures as low as 600 °C. Grain growth in thin YSZ films followed Arrhenius equation with an activation energy approximately 0.45 eV. The residual strain in YSZ films decreased with increasing annealing temperature from 600 to 900 °C

Doubly resonant optical nanoantenna arrays for polarization resolved measurements of surface-enhanced Raman scattering

We report that rhomb-shaped metal nanoantenna arrays support multiple plasmonic resonances, making them favorable bio-sensing substrates. Besides the two localized plasmonic dipole modes associated with the two principle axes of the rhombi, the sample supports an additional grating-induced surface plasmon polariton resonance. The plasmonic properties of all modes are carefully studied by far-field measurements together with numerical and analytical calculations. The sample is then applied to surface-enhanced Raman scattering measurements. It is shown to be highly efficient since two plasmonic resonances of the structure were simultaneously tuned to coincide with the excitation and the emission wave- length in the SERS experiment. The analysis is completed by measuring the impact of the polarization angle on the SERS signal.Comment: 13 pages, 5 figure

Grain Size Effect on the Induced Piezoelectric Properties of 0.9PMN-0.1PT Ceramic

Lead magnesium niobate-lead titanate (Pb(Mg1/3Nb2/3)O3 - PbTiO3 (PT) solid solutions have been widely researched to produce devices that can be used in low- and high-electric-field applications. For some applications, such as medical ultrasonic transducers, it is necessary to prepare the ceramic with high density and small average grain size. The effect of grain size on the low- and high-field properties of 0.9-PMN-0.10-PT ceramics is described in the present work. To prepare highly dense ceramic, vibratory and attrition milled powders were sintered between 1000 and 1250 ⁰C. The average grain sizes of the sintered ceramics varied from 0.7 to 3.5 micrometers. To understand the grain size effect, dielectric, pyroelectric, electrostrictive, and induced piezoelectric properties were studied