Structure and properties of complex hydride perovskite materials

• Published in: Nature communications 2014-12, Vol.5 (1), p.5706-5706, Article 5706
• Main Authors: Schouwink, Pascal, Ley, Morten B., Tissot, Antoine, Hagemann, Hans, Jensen, Torben R., Smrčok, Ľubomír, Černý, Radovan
• Format: Article
• Language: English
• Subjects: 639/301/119/1002; Chemistry; Humanities and Social Sciences; Hydrogen; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6706

Perovskite materials host an incredible variety of functionalities. Although the lightest element, hydrogen, is rarely encountered in oxide perovskite lattices, it was recently observed as the hydride anion H − , substituting for the oxide anion in BaTiO 3 . Here we present a series of 30 new complex hydride perovskite-type materials, based on the non-spherical tetrahydroborate anion BH 4 − and new synthesis protocols involving rare-earth elements. Photophysical, electronic and hydrogen storage properties are discussed, along with counterintuitive trends in structural behaviour. The electronic structure is investigated theoretically with density functional theory solid-state calculations. BH 4 -specific anion dynamics are introduced to perovskites, mediating mechanisms that freeze lattice instabilities and generate supercells of up to 16 × the unit cell volume in AB (BH 4 ) 3 . In this view, homopolar hydridic di-hydrogen contacts arise as a potential tool with which to tailor crystal symmetries, thus merging concepts of molecular chemistry with ceramic-like host lattices. Furthermore, anion mixing BH 4 − ← X − ( X − =Cl − , Br − , I − ) provides a link to the known ABX 3 halides. Complex metal hydrides are of interest for applications such as hydrogen storage, solid-state phosphors and solid electrolytes. Here the authors present the synthesis and properties of 30 complex hydride compounds with a perovskite crystal structure, based on the BH4 − anion and new synthesis protocols involving rare-earth elements.