Luminescence of the Narrow-Band Red Emitting Nitridomagnesosilicate Li₂(Ca_1–xSr_x)₂[Mg₂Si₂N₆]:Eu²⁺ (x = 0–0.06)

The nitridomagnesosilicates Li₂Ca₂[Mg₂Si₂N₆]:Eu²⁺ and Li₂(Ca_1.88Sr_0.12)­[Mg₂Si₂N₆]:Eu²⁺ show narrow-band red emission at 638 and 634 nm, respectively, with an emission bandwidth of 62 nm (∼1513 cm^–1) after excitation in the blue spectral region. Ce³⁺-doped samples show luminescence in the green spectral range (λ_em = 540 nm). The compounds were synthesized via solid-state metathesis reaction in Li melts. Refinement of single-crystal X-ray diffraction data revealed that Li₂(Ca_1.88Sr_0.12)­[Mg₂Si₂N₆] crystallizes isomorphic to Li₂Ca₂[Mg₂Si₂N₆]: C2/m [Z = 2, a = 5.5744(2), b = 9.8439(3), c = 6.0170(2) Å, β = 97.2520(10)°, R₁ = 0.021, wR₂ = 0.047]. Crystal composition was checked by EDS and ICP-OES measurements and luminescence properties are compared to state of the art narrow-band red emitting luminophors. On the basis of its narrow-band emission, application of the novel red luminophor in high CRI white pcLEDs is promising.