Synthesis and Luminescence Properties of Amber Emitting La7 Sr[Si10 N19 O3 ] : Eu2+ and Syntheses of the Substitutional Variants RE8-x AEx [Si10 N20-x O2+x ] : Eu2+ with RE=La, Ce; AE=Ca, Sr, Ba; 0≤x≤2.

Abstract

The oxonitridosilicate La7Sr[Si10N19O3] : Eu2+ and its substitutional variants RE 8‐x AEx [Si10N20‐x O2+x ] : Eu2+ with RE=La, Ce; AE=Ca, Sr, Ba and 0≤x≤2 were synthesized starting from REN, SrN/Ca3N2/Ba2N, SiO2, amorphous Si3N4 and Eu2O3 as doping agent at 1600 °C in a radiofrequency furnace. The crystal structure of La7Sr[Si10N19O3] was solved and refined based on single‐crystal X‐ray diffraction data. La7Sr[Si10N19O3] crystallizes in the orthorhombic space group Pmn21 (no. 31). The crystal structures of the isotypic compounds RE 8‐x AEx [Si10N20‐x O2+x ] were confirmed by Rietveld refinements based on powder X‐ray diffraction data using the single‐crystal data of La7Sr[Si10N19O3] as starting point. Crystal structure elucidation reveals a 3D network of vertex sharing SiN4 and SiN2(N1/2‐x/4O1/2+x/4)2 (0≤x≤2) tetrahedra. When excited with UV to blue light, La7Sr[Si10N19O3] : Eu2+ shows amber luminescence with λ em=612 nm and fwhm=84 nm/2194 cm−1, which makes it interesting for application in amber phosphor‐converted light emitting diodes.