Narrow-band red emitting oxonitridosilicate phosphor La4−xSr2+xSi5N12−xOx:Pr3+ (x ≈ 1.69)

The new oxonitridosilicates Ln4−xSr2+xSi5N12−xOx (Ln = La, Ce) were synthesized by high temperature solid-state reactions. The crystal structures were solved and refined from both single-crystal and powder X-ray diffraction data. These oxonitridosilicate compounds crystallize in the monoclinic space group P21/n (no. 14) and exhibit a double-layer structure made up of corner-sharing Si(O/N)4 tetrahedra. When excited with near-UV and blue light, the Pr3+ doped La2.31Sr3.69Si5N10.31O1.69 phosphor shows a narrow-band red emission peaking at 625 nm with a full width at half-maximum of 40 nm.