A cyan-emitting BaSi₇ N₁₀: Eu²⁺ phosphor prepared by gas reduction and nitridation for UV-pumping white LEDs

An Eu²⁺ -activated BaSi₇ N₁₀ cyan phosphor for UV-pumping white light-emitting diodes (LEDs) was successfully synthesized by direct gas reduction and nitridation of the homogeneous oxide precursor of a BaO- SiO₂ - Eu₂ O₃ system in flowing NH ₃ and CH₄ mixture gas. The phase purity, morphology, chemical composition, and luminescence properties were investigated. The effect of activator concentration on the optical properties of Eu²⁺ in BaSi₇ N₁₀ was discussed. The synthesized powders have a nearly pure BaSi₇ N₁₀ phase and consist of microsized particles. Eu²⁺ -doped BaSi₇ N₁₀ phosphors absorb strongly in the UV part of the electromagnetic spectrum and exhibit an intense cyan emission band centered at 482-500 nm, which agrees with earlier papers. The optical properties depend greatly on the Eu²⁺ concentration. Under an UV excitation, BaSi₇ N₁₀: Eu ²⁺ phosphors doped with a 20 atom % activator give the best luminescent properties, such as high emission intensity, high quantum efficiency, and very low thermal quenching, which suggests that Eu²⁺ -doped BaSi₇ N₁₀ can be a good green-blue phosphor for UV-pumping white LEDs.