Перенос заряда и центры F типа в щелочноземельных фторидах, активированных ионами Cd-=SUP=-2+-=/SUP=- или Zn-=SUP=-2+-=/SUP=-

The photoluminescence spectra of impurity centers containing the anionic vacancy Cd+va or Zn+va in alkaline-earth fluorides are studied. A comparison with the luminescence spectra of photochromic centers (РC), which can be considered as perturbed F centers, shows that the luminescence of the Cd+va or Zn+va centers is similar to the luminescence of F centers and, therefore, is associated with charge transfer from an impurity ion to an anionic vacancy.

Anionic vacancy-dependent activity of the CoSe2 with a tunable interfacial electronic structure on the N-doped carbon cloth for advanced Li–O2 batteries

The inferior reversibility of the formation/decomposition of the lithium peroxide (Li2O2) and its insolubility and insulation features result in poor energy efficiency and limited durability of state-of-the-art Li–O2 batteries.

Direct Formation and Structural Characterization of Electride C12A7

Ca12Al14O33 (C12A7 or Mayenite) is a material whose caged clathrate structure and occluded anionic species leads to significant functionality. The creation of occluded anionic vacancies leads to the injection of localized electrons at the center of the cage, converting the wide band gap insulator to a semi- or metallic conducting material. The conversion to the electride historically requires the synthesis of oxy-C12A7, consolidation, and then reduction to introduce anionic vacancies. This report develops and characterizes an electride formation procedure from three starting points: unconsolidated oxy-C12A7, heterogenous solid-state reactants (CaCO3 and Al2O3), and homogenous non-carbonaceous polymer assisted sol-gel reactants. Electride-C12A7 formation is observed in a vacuum furnace where the reactants are in direct contact with a carbon source. Process time and temperature-dependent structural characterization provides insight into the source of high temperature C12A7 stability, the mechanism of anionic vacancy formation, and the magnitude of ultimate conductivity that cannot be explained by current reduction theories. A new theory is presented where mixed O- and C-occupied cages lead to high temperature stability, oxidation of C species creates anionic vacancies, and an equilibrium between the reducing power of the electride-C12A7 and of the C species leads to the ultimate conductivity achieved by the process. This represents a shift in understanding of the carbonaceous reduction process and the first report of high purity electride-C12A7 formation from heterogenous solid-state reactants and homogenous non-carbonaceous polymer assisted sol-gel reactants.