Structure and Photoluminescence Properties of EuSiN₂

Abstract With the europium nitridosilicate, EuSiN2 a novel member of the multifaceted MSiN2 family is presented and compared with the structural similar compounds MSiN2 (M = Ca, Sr, Ba). A different way of presenting the structure as M-N polyhedra layers is introduced. The crystal structure of EuSiN2, being isotypical to SrSiN2, was determined and refined based on powder X-ray diffraction data in space group P21/c (no. 14) with a = 5.96381(2) Å, b = 7.25982(3) Å, c = 5.488338(19) Å, ? = 113.33°, V = 218.18(5) Å3, and Z = 4. As the Eu2+-doped MSiN2 compounds show excellent luminescence properties as LED phosphors, the luminescence behaviour of dark red emitting EuSiN2 has been investigated as well. Two emission peaks are visible at 708 nm and 764 nm. Many europium-doped nitridosilicates show more or less developed shoulders for their luminescence peaks, but two clearly shaped emission peaks are a novel feature for nitridosilicates. Comprehensive and detailed comparisons are given and discussed based on works in literature. The chromaticity coordinate positions of EuSiN2 in the CIE 1931 diagram are x = 0.678 and y = 0.284.