Epitaxial Thin Films as a Model System for Li-Ion Conductivity in LiTiO.

Using an epitaxial thin-film model system deposited by pulsed laser deposition (PLD), we study the Li-ion conductivity in LiTiO, a common anode material for Li-ion batteries. Epitaxy, phase purity, and film composition across the film thickness are verified employing out-of-plane and in-plane X-ray diffraction, transmission electron microscopy, time-of-flight mass spectrometry, and elastic recoil detection analysis. We find that epitaxial LiTiO behaves like an ideal ionic conductor that is well described by a parallel RC equivalent circuit, with an ionic conductivity of 2.

Synthesis of novel cyclosiloxane monomers containing push-pull moieties and their anionic ring opening polymerization.

The synthesis of three novel tetracyclosiloxane monomers modified either with a nitroaniline (NA) or with a Disperse Red 1 (DR1) push-pull group and their ring opening polymerization reaction in the presence of tetramethylammonium hydroxide are presented. The prepared monomers and polymers were characterized by different spectral methods and gel permeation chromatography. For the crystalline monomers, the structures were further proven by single crystal X-ray diffraction.

Luminescent and Photoconductive Layered Lead Halide Perovskite Compounds Comprising Mixtures of Cesium and Guanidinium Cations.

Interest in hybrid organic-inorganic lead halide compounds with perovskite-like two-dimensional crystal structures is growing due to the unique electronic and optoelectronic properties of these compounds. Herein, we demonstrate the synthesis, thermal and optical properties, and calculations of the electronic band structures for one- and two-layer compounds comprising both cesium and guanidinium cations: Cs[C(NH)]PbI (I), Cs[C(NH)]PbBr (II), and Cs[C(NH)]PbBr (III). Compounds I and II exhibit intense photoluminescence at low temperatures, whereas compound III is emissive at room temperature.

Why the dipolar response in dielectrics and spin-glasses is unavoidably universal.

Materials response to electric or magnetic fields is often dominated by the dynamics of dipoles in the system. This is for instance the case of polar dielectrics and many transition metal compounds. An essential and not yet well understood fact is that, despite their structural diversity, dielectric solids exhibit a striking universality of frequency and time responses, sharing many aspects with the behaviour of spin-glasses.

YAlC: A Bonding Chameleon with Heteropolyacetylene Features.

YAlC was prepared by a flux method. It crystallizes as a partially filled-up TlI structure, showing remarkable structural aspects at the border between Zintl phases and intermetallics. This novel ternary aluminide-carbide exhibits a unique one-dimensional multi-center bond and a polyacetylene-related aluminum carbide substructure.

Crystal structure and electronic properties of Y3AlC3.

A novel ternary aluminum carbide, Y(3)AlC(3), has been synthesized under application of a lithium metal flux at high temperature (1523 K). Single-crystal structure determination of this compound revealed a new structure type with the Wyckoff sequence 2j3e and remarkable structural features at the border between Zintl and intermetallic phases. The puzzling bonding structure of Y(3)AlC(3) is analyzed with the aid of electronic structure calculations (energy bands and the electron localization function).