Weak thermal quenching of the luminescence in Y2.94-xLuxAl4GaO12: 0.06Ce(3+) green phosphor for white light-emitting diodes

摘要

A series of Y2.94-xLuxAl4GaO12: 0.06Ce(3+) phosphors were prepared by the conventional solid-state reaction method. It was confirmed that the phosphors exhibit cubic garnet crystal structures by XRD and Rietveld refinements. The phosphors show an intense broad emission band from 475 nm to 650 nm, which attributed to the 5d -> 4f transitions of the Ce3+ ions under the excitation of 450 nm. Simultaneously, obvious blue shift is observed from 518 nm to 497 nm with increasing Lu3+ concentrations from 0 to 2.94. With the increase of Lu3+ concentrations the emission intensity increases and reaches to the maximum for x = 2.5. By optimizing Lu3+ concentration, the quantum efficiency up to 89.8% is obtained. The emission intensity at 453 K is up to 92% of that at room-temperature indicating a weak thermal quenching and a superior thermal stability. These results indicate that the phosphor can be used in blue LED-Chip based white LEDs in the future.