# Structure and Photoluminescence Properties of EuSiN2

## TL;DR

EuSiN2 is a new europium-based compound with a unique structure and two distinct red light emission peaks, useful for LED applications.

## Contribution

EuSiN2 introduces a novel structure representation as M-N polyhedra layers and exhibits two clearly shaped luminescence peaks, a new feature in nitridosilicates.

## Key findings

- EuSiN2's crystal structure was determined in space group P21/c with specific lattice parameters.
- EuSiN2 shows two distinct emission peaks at 708 nm and 764 nm, a novel feature among nitridosilicates.
- The chromaticity coordinates of EuSiN2 are x = 0.678 and y = 0.284 in the CIE 1931 diagram.

## 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, β = 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.

With EuSiN2 a novel Eu‐nitridosilicate is presented including a very comprehensive structure description and a comparison with its related compounds MSiN2. A different way of displaying the structure as M‐N polyhedra layers is introduced. The dark red luminescent EuSiN2 exhibits two clearly shaped luminescent peaks which present a novel feature for nitridosilicates.