Near UV-pumped green-emitting Na3(Y,Sc)Si3O9:Eu2+ phosphor for white-emitting diodes

Abstract

A series of iso-structural green-emitting Na₃(Y,Sc)Si₃O₉:Eu²⁺ phosphors with different Y/Sc ratios have been synthesized by a solid-state reaction. All of the phosphors exhibited strong broad absorption bands in the near ultraviolet (n-UV) range, and gave bright green emission upon 365 nm excitation light. As for the composition-optimized Na₃Y_0.3Sc_0.7Si₃O₉:Eu²⁺ phosphor, the critical Eu²⁺ quenching concentration (QC) was determined to be about 3 mol%, and the corresponding QC mechanism was verified to be the dipole–quadrupole interaction. The fluorescence decay curves, temperature dependence photoluminescence and CIE value of Na₃Y_0.3Sc_0.7Si₃O₉:Eu²⁺ phosphors were discussed. A white light-emitting diode (LED) lamp was fabricated based on the green-emitting Na₃Y_0.3Sc_0.7Si₃O₉:Eu²⁺ phosphor and combining a 370 nm n-UV chip and the commercial blue-emitting BaMgAl₁₀O₁₇:Eu²⁺ and red-emitting CaAlSiN₃:Eu²⁺ phosphors. The produced white-light n-UV LED lamp gave CIE chromaticity coordinates of (0.3690, 0.3782), a high color rendering index of 85.6 and a warm color temperature of 2300 K.