Abstract: Carbonate coprecipitate precursors were prepared by mixed nitrate solutions containing M²⁺(M²⁺＝Sr²⁺, Ba²⁺), Y³⁺ and Er³⁺ as the cation sources and (NH₄)₂CO₃ as the precipitator. MY₂S₄∶Er³⁺ phosphors were synthesized by calcining the carbonate precursors with CS2 as the sulfurization reagent at 1050 ℃ for 4 h. XRD patterns show that the synthesized SrY₂S₄ and BaY₂S₄ crystalline powders possess the orthorhombic [CaFe₂O₄]-type structure. Photoluminescent measurements indicate that there were mainly red emitting(⁴F_9/2→⁴I_15/2) and green emitting(²H_11/2→⁴I_15/2 and ⁴S_3/2→⁴I_15/2) of Er³⁺ in the SrY₂S₄ while there was only red emitting(⁴F_9/2→⁴I_15/2) in BaY₂S₄∶Er³⁺. BaY₂S₄∶Er³⁺ is considered as a novel red phosphor candidate with a high monochromaticity.

Key words: Alkaline-earth rare-earth sulfide, Erbium ion, Red phosphor, Monochromaticity