A red-emitting Sr3La(1−x)Eux(AlO)3(BO3)4 phosphor with high thermal stability and color purity for near-UV-excited wLEDs

Abstract

A high efficiency red-emitting Eu³⁺ doped Sr₃La(AlO)₃(BO₃)₄ phosphor has been calcined successfully through a traditional solid-state method, and the photoluminescence and cathode-luminescence properties of samples are investigated in detail. The result of density functional theory (DFT) calculation shows that the Sr₃La(AlO)₃(BO₃)₄ host lattice has an indirect band gap. The broad excitation ranges from 200 nm to 500 nm, especially the strongest excitation located in the near ultraviolet (near-UV) region, suggests that the phosphor can match well with not only blue LED chips but also near-UV LED chips. Besides, the phosphor can emit bright red light peaking at 596, 618, 655 and 706 nm under either near-UV or blue light excitation and the internal quantum efficiency can reach 40%. The temperature-dependent PL properties and calculation of color purity show that the phosphor has an excellent thermal stability and outstanding color stability. Ultimately, by employing Sr₃La(AlO)₃(BO₃)₄:Eu³⁺ phosphor as a red light component, a stable warm white light emission is obtained with Ra = 80, CIE = (0.3443, 0.2903) and CCT = 4680 K. These results indicate that red Sr₃La(AlO)₃(BO₃)₄:Eu³⁺ phosphor may have a great potential for wLEDs with fantastic properties.