A blue-emitting Sc silicate phosphor for ultraviolet excited light-emitting diodes

Abstract

A blue-emitting phosphor BaSc₂Si₃O₁₀:Eu²⁺ was synthesized using the conventional solid-state reaction. The crystallographic occupancy of Eu²⁺ in the BaSc₂Si₃O₁₀ matrix was studied based on the Rietveld refinement results and the photoluminescence properties. BaSc₂Si₃O₁₀ exhibits blue emission ascribed to ³T₂–¹A₁ and ³T₁–¹A₁ charge transfer of SiO₄⁴⁻ excited by 360 nm. All the phosphors of BaSc₂Si₃O₁₀:Eu²⁺ exhibit strong broad absorption bands in the near ultraviolet range, and give abnormal blue emission upon 330 nm excitation. The abnormal phenomenon was explored in detail through many pieces of experimental evidence. The concentration of Eu²⁺ is optimized to be 3 mol% according to emission intensity and the quenching mechanism is verified to be a quadrupole–quadrupole interaction. The CIE coordinates of BaSc₂Si₃O₁₀:0.03Eu²⁺ are calculated to be (0.15, 0.05) and BaSc₂Si₃O₁₀:0.03Eu²⁺ shows similar thermal stability to commercial BaMgAl₁₀O₁₇:Eu²⁺.