Y(HSeO3)(SeO3)(H2O)·(H2O) and Y2(SeO3)2(SeO4)(H2O)2·(H2O)0.75: Two yttrium selenites with a short UV cut-off edge explored from pure selenite compounds

Abstract

Two UV inorganic yttrium selenite optical materials, namely, Y(HSeO3)(SeO3)(H2O)·(H2O) (1) and Y2(SeO3)2(SeO4)(H2O)2·(H2O)0.75 (2), have been synthesized successfully by hydrothermal reactions. Of these, Y2(SeO3)2(SeO4)(H2O)2·(H2O)0.75 (2) is a new mixed valent selenium oxide containing Se(IV) and Se(VI) cations simultaneously. Y(HSeO3)(SeO3)(H2O)·(H2O) (1) shows a 3D structure composed of 2D yttrium selenite layers linked by O−H···O bonds. Y2(SeO3)2(SeO4)(H2O)2·(H2O)0.75 (2) exhibits a 3D structure composed of 2D yttrium selenite layers connected by SeO4 tetrahedron. Y(HSeO3)(SeO3)(H2O)·(H2O) (1) crystallized in a chiral space group P212121 and could display a moderate SHG intensity about 0.7 times of the commercial KH2PO4 (KDP). Its powder laser damage threshold quantity was estimated to be 120.2 MW/cm2, which is about 46.2 times that of AGS (2.6 MW/cm2). UV–vis–NIR spectra reflectance spectra showed that these solids are wide band gap compounds with Eg of 5.5 and 5.1 eV respectively. Theoretical calculations disclosed that Y(HSeO3)(SeO3)(H2O)·(H2O) (1) is an indirect band gap structures and its bandgaps is determined by O and Se atoms.