Recent Advances in Rare Earth-Doped Hydrides

The optical properties of rare earth ions in different inorganic host materials, for instance oxides, silicates, borates, or nitrides, have been used in applications for many years, from color TV to fluorescent tubes, lasers, or pc-LEDs. However, rare earth metal ion-doped hydrides have not really been considered as host lattices and up to now only been studied in a relatively small number of investigations. Yet, for certain metal hydrides these studies, e.g., allowed the determination of the crystal field strength and nephelauxetic effect of the hydride anion using the Eu2+ 5d excited state. In air-sensitive hydrides, the use may be restricted to fundamental studies and local probes. But recently more and more air-stable mixed anionic hydrides have been discovered, which may serve as hosts. This short review summarizes the synthesis and characterization of rare earth metal ion-doped hydrides reported so far.