Tuning β-Si3Al3O3N5 phosphors by Eu or Ce doping for white light-emitting diodes (wLEDs)

Abstract

SiAlON-based phosphors have garnered considerable attention in the field of white lighting owing to their excellent thermal stability, and rare earth doped SiAlON-based phosphors are expected to be used in a new generation of lighting sources. In this work, Eu2+ or Ce3+ doped Si3Al3O3N5 phosphors were synthesized by high temperature solid phase method. The microstructure of the phosphors exhibited irregular grain. The two phosphors exhibit green and cyan luminescence under 365 nm excitation, which are derived from the 5d-4f transitions of Eu2+ and Ce3+, respectively. The quenching concentrations are 3 % and 4 % for Eu2+ and Ce3+doped phosphors, respectively. The fluorescence intensity of Eu2+ and Ce3+ activated SiAlON powders decreased to 50 % of the room temperature intensity at 179 °C and 170 °C, respectively. The thermal activation energy values of the two phosphors were 0.35 eV, and the coordinate configuration diagram was constructed to comprehensively analyze the thermal quenching behavior of phosphors. Finally, the two phosphors powders were mixed with red and blue fluorophore to obtain white LEDs, showing low color temperature, high color rendering, high power unsaturation and long half-life. The SiAlON-based phosphors with excellent thermal stability obtained in this work achieve different wavelengths of luminescence in the green region. The results show that the β-Si3Al3O3N5 phosphor can be used as a candidate material for high-quality green light supplement for wLEDs.