Titania (TiO2) is employed as a host for the Eu3+ activator ion. Thin films were produced by the sol-gel method on silicon and corning glass substrates and, depending on the nature of the substrate, they present different crystalline structure. The films show an intense red photoluminescence associated with the D05→7F2 transition of the electronic structure of Eu3+. The photoluminescence presents better characteristics for the films deposited on silicon wafers. For above band gap excitation the emission from the TiO2 matrix is obscured by the luminescence of the Eu3+ ions. The peak energy position, the spectral shape, and the width are insensitive to changes of temperature in the 12–300 K range, making the TiO2:Eu3+ a very attractive system for technological applications.

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We have reviewed the convenience and possibility of utilizing thallium-based HT c superconductors for power applications. Some basic properties of Tl-based systems such as the crystal structure, phase stability, weak-links, pinning problems and irreversibility lines are discussed first. Two basic approaches to conductor preparation are then described, the closed and the open one. Special attention is focused on the fabrication of Tl-1223 and Tl-2223 superconductors. In the case of the more successful open approach a two-step technological procedure is usually chosen: first, the basic precursor material without Tl is synthesized, then second, the precursor is thallinated in a one-or two-zone reaction chamber. The most important precursor preparation techniques are described including aerosol deposition from either solution or ink, electro-deposition, sol-gel methods such as spin-and dip-coating and screen-printing and painting. Finally, some properties of the produced conductors important for power applications are presented.

When titanium dioxide films are deposited by delivering a liquid aerosol of titanium-n-butoxide or titanium diisopropoxide, the crystalline and morphological features indicate that the deposition takes place through an aerosol-assisted chemical-vapor deposition (AA-CVD) process. However, the crystalline state depends on the precursor. The evidence of AA-CVD is strongly supported by the quantitative study of the growth rate rg as a function of deposition temperature. The fitting of the experimental rg curves to the equation ∼T3∕2exp(−EA∕RT) indicates that film formation is limited by the gas diffusion + surface reaction of the precursors. The characteristic activation energy EA of such surface reaction depends on the Ti precursor; EA≅112.0kJ∕mol for Ti-n-butoxide and EA≅21.4kJ∕mol for Ti-diisopropoxide.