Overcoming the cyan gap for full‐spectrum lighting using cation‐substitution‐induced rigid Ca 2 YZr 2 Al 3 O 12 :Ce 3+

Abstract Mixing multicolor phosphors for simulating the full spectrum of sunlight illumination is a popular solution to obtain high‐quality white light. However, there is still a need to overcome the cyan gap in the emission spectrum. In this work, a series of garnet Ca 2 Y 0.94– x Lu x Zr 2– y Hf y Al 3 O 12 :6%Ce 3+ (abbreviated as CY 0.94– x Lu x Zr 2– y Hf y A:Ce 3+ ) cyan phosphors are designed and prepared by substituting Y 3+ and Zr 4+ in Ca 2 YZr 2 Al 3 O 12 :6%Ce 3+ with Lu 3+ and Hf 4+ with smaller ionic radius and larger mass. Under 405 nm violet light excitation, the optimized Ca 2 Y 0.88 Lu 0.06 Hf 2 Al 3 O 12 :6%Ce 3+ (CY 0.88 Lu 0.06 Hf 2 A:Ce 3+ ) shows a bright cyan emission band in the range of 430–750 nm with the peak at 477 nm. Importantly, the emission intensity and thermal stability properties of CY 0.88 Lu 0.06 Hf 2 A:Ce 3+ were significantly improved by 58% and 47% compared to those of pure Ca 2 YZr 2 Al 3 O 12 :Ce 3+ . Small and heavy cation substitution could induce highly stable rigid structure, thus enhancing emission intensity and stability. The color rendering index increases from 84.5 to 92.0 after supplementing CY 0.88 Lu 0.06 Hf 2 A:Ce 3+ phosphor in white light‐emitting diode devices combining commercial red, green, and blue phosphors with a violet chip, indicating its practical application in full‐spectrum lighting. The present study provides promising strategies for the design and development of efficient cyan materials for high‐quality full visible spectrum light‐emitting diode lighting.