Novel Green-emitting BaY2Al4SiO12:Ce3+ Garnet Phosphors with Superior Internal Quantum Efficiency for High Color Rendering White LEDs

Efficient green phosphors with high internal quantum efficiency (IQE) are crucial for developing high color rendering white light-emitting diodes (LEDs). Herein, through co-substituting cation sites, Y 3+ /Al 3+ are replaced by Ba 2+ /Si 4+ respectively in the Y 3 Al 5 O 12 (YAG) lattice, yielding novel Ce 3+ -doped BaY 2 Al 4 SiO 12 (BYAS) green phosphors with symmetrical and stable structure similar to that of YAG. Notably, the BY 1.94 AS:0.06Ce 3+ phosphor exhibits exceptional IQE of 96.4%. Upon adjusting the Ce 3+ doping concentration, the optimal BY 1.94 AS:0.06Ce 3+ phosphor shows green emission at 533   nm and a broad full width at half maximum of 87   nm under 469   nm excitation. The emission spectrum ranges from 500 to 700   nm, primarily due to the characteristic 5d to 4   f transitions of Ce 3+ ions. The BY 1.94 AS:0.06Ce 3+ phosphor retains 67.7% of its initial intensity at 423   K (E a = 0.241   eV), demonstrating high thermal stability. As-prepared BY 1.94 AS:0.06Ce 3+ green phosphor and commercial CaAlSiN 3 :Eu 2+ red phosphors were combined with InGaN blue chip to fabricate a white LEDs device. The device exhibits warm white light with a high color rendering index (Ra = 85.9, R9 = 41.1), a low correlated color temperature (5064   K) and an excellent luminous efficiency (80.24   lm/W). This work suggests that the novel high-efficiency BYAS:Ce 3+ green phosphors possess significant potential for achieving high color rendering in warm-white LEDs.