Dielectric Behavior of Thin Polymerized Composite Layers Fabricated by Inkjet-Printing.

A detailed study of the dielectric behavior of printed capacitors is given, in which the dielectric consists of a thin (<1 µm) ceramic/polymer composite layer with high permittivities of ε 20-69. The used ink contains surface-modified BaSrTiO (BST), a polymeric crosslinking agent and a thermal initiator, which allows the immediate polymerization of the ink during printing, leading to homogenous layers. To validate the results of the calculated permittivities, different layer thicknesses of the dielectric are printed and the capacitances, as well as the loss factors, are measured.

Interpreting rheology and electrical conductivity: It all boils down to which particle size.

Hypothesis: The electrical charges that develop on the surface of the ceramic particles upon contact with water, due to the interaction with ions in solution, result in a liquid-solid interface, which utterly modifies the properties of individual particles and the way they interact with each other to form a structure. This work explores a new approach to the relationships between structure and stability of suspensions.

Experiments: For this purpose, suspensions with a constant 0.

Fabrication and Characterization of Fully Inkjet Printed Capacitors Based on Ceramic/Polymer Composite Dielectrics on Flexible Substrates.

The preparation of fully inkjet printed capacitors containing ceramic/polymer composites as the dielectric material is presented. Therefore, ceramic/polymer composite inks were developed, which allow a fast one-step fabrication of the composite thick films. BaSrTiO (BST) is used as the ceramic component and poly(methyl methacrylate) (PMMA) as the polymer.

Ferroelectric Properties of Perovskite Thin Films and Their Implications for Solar Energy Conversion.

Whether or not methylammonium lead iodide (MAPbI ) is a ferroelectric semiconductor has caused controversy in the literature, fueled by many misunderstandings and imprecise definitions. Correlating recent literature reports and generic crystal properties with the authors' experimental evidence, the authors show that MAPbI thin-films are indeed semiconducting ferroelectrics and exhibit spontaneous polarization upon transition from the cubic high-temperature phase to the tetragonal phase at room temperature. The polarization is predominantly oriented in-plane and is organized in characteristic domains as probed with piezoresponse force microscopy.

Lithium Diffusion Pathway in Li(1.3)Al(0.3)Ti(1.7)(PO4)3 (LATP) Superionic Conductor.

The Al-substituted LiTi2(PO4)3 powders Li(1+x)Al(x)Ti(2-x)(PO4)3 (LATP) were successfully prepared by a water-based sol-gel process with subsequent calcination and sintering. The crystal structure of obtained samples was characterized at different temperatures using high-resolution synchrotron-based X-ray and neutron powder diffraction. Possible lithium diffusion pathways were initially evaluated using the difference bond-valence approach.

High capacity vertical aligned carbon nanotube/sulfur composite cathodes for lithium-sulfur batteries.

Binder free vertical aligned (VA) CNT/sulfur composite electrodes with high sulfur loadings up to 70 wt% were synthesized delivering discharge capacities higher than 800 mAh g(-1) of the total composite electrode mass.

Local variations in defect polarization and covalent bonding in ferroelectric Cu(2+)-doped PZT and KNN functional ceramics at the morphotropic phase boundary.

Cu(2+)-doped Pb[Zr(0.54)Ti(0.46)]O(3) (PZT) and Cu(2+)-doped [K(0.

A device for noninvasive assessment of vascular impairment risk in the lower extremity.

The repeatability and resolution of the clinical gold standard of vascular assessment, the ankle-brachial index (ABI), was compared to that of a new device that dynamically assesses tissue perfusion during external loading utilizing laser Doppler flowmetry. Eight subjects of varying levels of vascular impairment were tested in successive weeks using two different sites on the subject's posterior calf. These new measures included the perfusion decrease as well as the unloading delay during cyclic loading.

Defect-Dipole Formation in Copper-Doped PbTiO3 Ferroelectrics.

The defect structure of hard copper-modified polycrystalline PbTiO3 ferroelectrics is investigated by means of electron paramagnetic resonance and hyperfine sublevel correlation spectroscopy, as well as density functional theory calculations. Special emphasis is put on the 207Pb-hyperfine couplings, which are resolved up to the third coordination sphere. The results prove that copper is incorporated at the octahedrally coordinated Ti site, acting as an acceptor.

Measuring electrostatic potential profiles across amorphous intergranular films by electron diffraction.

Amorphous 1-2-nm-wide intergranular films in ceramics dictate many of their properties. The detailed investigation of structure and chemistry of these films pushes the limits of today's transmission electron microscopy. We report on the reconstruction of the one-dimensional potential profile across the film from an experimentally acquired tilt series of energy-filtered electron diffraction patterns.

High-field/high-frequency EPR of paramagnetic functional centers in Cu2+- and Fe3+-modified polycrystalline Pb[Zr(x)Ti(1-x)]O3 ferroelectrics.

Copper(II)- and iron(III)-modified Pb[Zr(x)Ti(1-x)]O3 ferroelectrics were investigated by means of high-field/high-frequency EPR. The results obtained suggest that Cu2+ and Fe3+ both substitute as acceptor centers for [Zr,Ti]4+. Whereas for the iron-doped system the charge compensating oxygen vacancies (V(O)**) lead to the formation of charged (Fe'(Ti-)V(O)**)* defect associates, no such associates have been observed for the copper-modified system.

Electrical conductivity and stability of concentrated aqueous alumina suspensions.

This work describes the effect of solids load and ionic strength on the electrical conductivity (K(S)) of concentrated aqueous suspensions of commercial alpha-alumina (1-35 vol% solids). The results obtained show that the dependency of the electrical conductivity of the suspending liquid (K(L)) on the volume fraction of solids is well described by Maxwell's model. The change in the conductivity of the suspensions relative to that of the suspending liquid (K(S)/K(L)) was found to be inversely proportional to the solids content, as predicted by Maxwell's model.