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, Y³⁺/Al³⁺ are replaced by Ba²⁺/Si⁴⁺ respectively in the Y₃Al₅O₁₂ (YAG) lattice, yielding novel Ce³⁺-doped BaY₂Al₄SiO₁₂ (BYAS) green phosphors with symmetrical and stable structure similar to that of YAG. Notably, the BY_1.94AS:0.06Ce³⁺ phosphor exhibits exceptional IQE of 96.4 %. Upon adjusting the Ce³⁺ doping concentration, the optimal BY_1.94AS:0.06Ce³⁺ 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 Ce³⁺ ions. The BY_1.94AS:0.06Ce³⁺ phosphor retains 67.7 % of its initial intensity at 423 K (E_a = 0.241 eV), demonstrating high thermal stability. As-prepared BY_1.94AS:0.06Ce³⁺ green phosphor and commercial CaAlSiN₃:Eu²⁺ 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:Ce³⁺ green phosphors possess significant potential for achieving high color rendering in warm-white LEDs.