CaY2HfAl4O12:Ce3+ phosphor: A novel solution for cyan-gap compensation in high-R9/R15 full-spectrum white LEDs

Traditional white light-emitting diodes (LEDs) frequently exhibit cyan-gap deficiency, resulting in unbalanced emission spectrum that impedes the realization of full-spectrum lighting. Herein, a novel Ce 3+ -doped garnet phosphor CaY 2 HfAl 4 O 12 (CYHAO:Ce 3+ ) was successfully synthesized via a high-temperature solid-state reaction method. The crystal structure, luminescent properties, thermal stability, and WLED application performance of the phosphor were systematically investigated. X-ray diffraction (XRD) and Rietveld refinement results confirm that CYHAO:Ce 3+ crystallizes in a cubic garnet structure with space group Ia-3d. Under 446 nm blue light excitation, CYHAO:Ce 3+ exhibits a broad cyan emission band centered at ∼505 nm, which perfectly fills the cyan-gap of traditional WLEDs. The optimal Ce 3+ doping concentration is determined to be 0.02 mol. Concentration quenching mainly resulted from radiation reabsorption and electric dipole-electric dipole interactions. This phosphor exhibited strong thermal stability, retaining ∼73% of initial emission intensity at 423 K with an activation energy of 0.31eV. A WLED device fabricated by combining it with commercial CaAlSiN 3 :Eu 2+ phosphors and a 450 nm blue chip emitted warm white light with an excellent color rendering index (Ra = 92.8, R9 = 93.9, R15 = 91.7) and a correlated color temperature of 3507 K. These results demonstrate that CYHAO:Ce 3+ is a promising cyan phosphor for high-quality full-spectrum WLEDs with excellent color rendering performance.