Instituto de Química, LIEC, INCTMN, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
Published: May 2011
AI Article Synopsis
Article Abstract
Periodic first-principles calculations based on density functional theory at the B3LYP level has been carried out to investigate the photoluminescence (PL) emission of BaZrO(3) assembled nanoparticles at room temperature. The defect created in the nanocrystals and their resultant electronic features lead to a diversification of electronic recombination within the BaZrO(3) band gap. Its optical phenomena are discussed in the light of photoluminescence emission at the green-yellow region around 570 nm. The theoretical model for displaced atoms and/or angular changes leads to the breaking of the local symmetry, which is based on the refined structure provided by Rietveld methodology. For each situation a band structure, charge mapping, and density of states were built and analyzed. X-ray diffraction (XRD) patterns, UV-vis measurements, and field emission scanning electron microscopy (FE-SEM) images are essential for a full evaluation of the crystal structure and morphology.
High-temperature superconducting wires have many large-scale, niche applications such as commercial nuclear fusion as well as numerous other large-scale applications in the electric power industry and in the defense, medical and transportation industries. However, the price/performance metric of these coated conductor wires is not yet favorable to enable and realize most large-scale applications. Here we report on probing the limits of J (H, T) possible via defect engineering in heteroepitaxially deposited high-temperature superconducting thin-films on coated conductor substrates used for long-length wire fabrication.
Within the emerging field of proton-conducting fuel cells, BaZrYO (BZY10) is an attractive material due to its high conductivity and stability. The fundamentals of conduction in sintered pellets and thin films heterostructures have been explored in several studies; however, the role of crystallographic orientation, grains, and grain boundaries is poorly understood for proton conduction. This article reports proton conduction in a self-assembled multi-oriented BZY10 thin film grown on top of a (110) NdGaO substrate.
In order to understand how the doping with self-assembled nanorods of different sizes and concentrations as well as applied magnetic fields affect the critical current anisotropy in YBaCuO (YBCO) thin films close to YBCO c-axis, we present an extensive and systematic computational study done by molecular dynamics simulation. The simulations are also used to understand experimentally measured J(θ) curves for BaHfO, BaZrO and BaSnO doped YBCO thin films with the help of nanorod parameters obtained from transmission electron microscopy measurements. Our simulations reveal that the relation between applied and matching field plays a crucial role in the formation of J(θ)-peak around YBCO c-axis (c-peak) due to vortex-vortex interactions.
Perovskite-type ternary oxide nanostructured materials have gained great attention in recent years as promising materials for solar cell applications. However these ternary oxides have failed to be applied as a working electrode in DSSCs due to its poor performance and its inability to bind dye molecules to the surface. A heterostructure perovskite/TiO photoactive electrodes is a new strategy to improve the photon-to-current efficiency (PCE) of DSSCs.
Department of Mechanical Engineering, the Texas Center for Superconductivity, and Advanced Manufacturing Institute, University of Houston, Houston, TX, 77204, USA.
A main challenge that significantly impedes REBaCuO (RE = rare earth) coated conductor applications is the low engineering critical current density J because of the low superconductor fill factor in a complicated layered structure that is crucial for REBaCuO to carry supercurrent. Recently, we have successfully achieved engineering critical current density beyond 2.0 kA/mm at 4.
