Structure and Photoluminescence Properties of EuSiN.

With the europium nitridosilicate, EuSiN a novel member of the multifaceted MSiN family is presented and compared with the structural similar compounds MSiN (M = Ca, Sr, Ba). A different way of presenting the structure as M-N polyhedra layers is introduced. The crystal structure of EuSiN, being isotypical to SrSiN, was determined and refined based on powder X-ray diffraction data in space group P2/c (no. 14) with a = 5.96381(2) Å, b  = 7.25982(3) Å, c  = 5.488338(19) Å, β = 113.33°, V  = 218.18(5) Å, and Z  = 4. As the Eu-doped MSiN compounds show excellent luminescence properties as LED phosphors, the luminescence behaviour of dark red emitting EuSiN 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 EuSiN in the CIE 1931 diagram are x = 0.678 and y = 0.284.