Facile synthesis of rare earth ions doped LiSr4(BN2)3 phosphors for white light-emitting diodes

Abstract

Rare earth ions doped nitride is a kind of excellent phosphor for phosphor-converted white light-emitting diodes (WLEDs). However, the critical synthesis condition limits the application of nitrides in WLEDs. In this work, we develop a modified carbothermal reduction and nitridation method to synthesize rare earth ions doped LiSr4(BN2)3 phosphors. The crystal structure, morphology and photoluminescence properties of the obtained phosphors were systematically investigated. Intense blue emitting is achieved in Ce3+ doped LSBN with internal quantum efficiency (IQE) of 85.7 % and external quantum efficiency (EQE) of 45.5 %. The emitting color can be tuned from blue to green by co-doping with different amounts of Tb3+ ions. Near unit IQE is achieved in LSBN:Ce 0.5 mol%, Tb 5 mol%. The obtained phosphors exhibit excellent thermal and color stability at temperature range of 300–523 K. A WLED is fabricated by coating LSBN:Ce 0.5 mol%, Tb 5 mol% and commercial CaAlSiN3:Eu2+ on a 370-nm chip. The rare earth ions doped LSBN phosphors with high QE and excellent thermal stability in this work are promising candidates for WLEDs