A novel cyan-emitting Ca2LuZr2Al1.5Ga1.5O12:Ce3+ phosphor excited by violet light toward full-spectrum white LEDs

Abstract

The development of full-spectrum white LEDs is significantly hindered by the “cyan gap” in the 470–510 nm spectral region. Addressing this gap with moderate -quality cyan-emitting phosphors, efficiently excited by violet LED chips, is crucial for achieving high color rendering index (Ra >90) illumination. In this study, a novel and moderate efficient garnet-structured cyan-emitting phosphor Ca₂LuZr₂Al_1.5Ga_1.5O₁₂:Ce³⁺ (CLZAGO:Ce³⁺) was effectively prepared via a high-temperature solid-state reaction route. When excited at 410 nm, the optimized CLZAGO:0.04Ce³⁺ sample displays a robust cyan emission peaking at 484 nm, accompanied by a broad emission band spanning 420–650 nm and a full width at half-maximum (FWHM) of 90 nm, which efficiently fills the cyan gap commonly observed in conventional White light-emitting diodes (WLEDs). The phosphor exhibits available thermal stability, preserving 53 % of its room-temperature emission intensity at 423 K, and achieves a moderate external quantum efficiency (EQE) of 45.43 %. Finally, when CLZAGO:Ce³⁺ was combined with commercial blue-emitting Sr₅(PO₄)₃Cl:Eu²⁺ (SPOC:Eu²⁺), green-emitting (Ba, Sr)₂SiO₄:Eu²⁺ (BSSO:Eu²⁺), and red-emitting CaAlSiN₃:Eu²⁺ (CASN:Eu²⁺) phosphors and integrated into a 410 nm violet LED chip, a full-spectrum WLED with an enhanced Ra of 95 was achieved. These findings underscore the critical role of CLZAGO:Ce³⁺ as a promising cyan-emitting component for next-generation high color-rendering full-spectrum WLEDs.