A Strategy for the Synthesis of Oxonitridosilicate Phosphors from Anionic Condensation

The exploration of new luminescent materials is driven by potential applications in solid-state lighting and display technologies. In this paper, we employed an anionic condensation approach to craft novel oxonitridosilicate compounds by substituting 3O^2– with 2N^3– in a carefully selected system. This approach enabled us to synthesize a highly condensed oxonitridosilicate compound LaSr₄Si₅N₉O₂, which crystallizes in the orthorhombic crystal system with the space group Ama2 (no. 40) and lattice parameters a = 9.2986(1) Å, b = 23.4382(1) Å, c = 5.371(1) Å, V = 1170.55(1) ų, and Z = 4. The condensation appears inside the layer, with dreier rings originating from neighboring tetrahedra connected by bridging nitride (N^[2]). This enriches the possibility of using the approach to design multiple layered or other featured oxonitridosilicates. Furthermore, we investigated the luminescence properties when doped with rare-earth ions. The Pr³⁺-doped LaSr₄Si₅N₉O₂ exhibits a remarkably narrow-band red emission (λ_em ≈ 618 nm, fwhm ≈ 54 nm) when excited by UV and blue light.