Highly efficient cyan-green-emitting phosphors are urgently needed for high-color-quality full-visible-spectrum white light-emitting diodes (LEDs). Herein, we report on efficient near-ultraviolet-excited cyan-green-emitting Ca₂La_1-xLu_xHf₂Al₃O₁₂:Ce³⁺ (CLa_1-xLu_xHA:Ce³⁺) garnet phosphors, which are developed based on the solid-solution design of chemical cation substitution. All phosphor samples present a garnet crystal structure with the $Ia\bar{3}d$ space group; with increasing Lu³⁺ ions content, the lattice could be gradually contracted, along with a high symmetry as well as rigidity. Furthermore, under the 408 nm excitation, the cyan-green emissions of CLa_1-xLu_xHA:Ce³⁺ phosphors are progressively enhanced with a slight blue-shift, due to crystal field splitting and Stokes shift. Importantly, quantum efficiency and thermal stability performances are greatly improved by introducing smaller Lu³⁺ ions to replace the bigger La³⁺ ions, owing to the high rigidity structure with high symmetry. The optimized CLa_0.5Lu_0.5HA:Ce³⁺ phosphor exhibits an intense cyan-green emission band with high internal quantum efficiency of 76.4% and external quantum efficiency of 54.4%. Through employing the as-prepared CLa_0.5Lu_0.5HA:Ce³⁺ cyan-green phosphor, we have successfully fabricated a full-visible-spectrum LED device, demonstrating a bright warm-white light emission with an extremely high color rendering index (Ra = 98.0, R9 = 95.9, and R12 = 94.3) and low correlated color temperature (3497 K) under 100 mA driving current. This study not only reveals the correlation between the crystal structure evolution and luminescent properties of phosphor materials, but also provides new strategies for the design and development of novel efficient luminescent materials for high-quality full-visible-spectrum LED lighting.

高颜色质量的全可见光谱白光发光二极管 (LED) 迫切需要高效的青绿色荧光粉。在此，我们报道了高效的近紫外激发的青色-绿光 Ca ₂ La _{1- x} Lu _x Hf ₂ Al ₃ O ₁₂ :Ce ³⁺ (CLa _{1- x} Lu _x HA:Ce ³⁺ ) 石榴石荧光粉，是基于化学阳离子置换的固溶设计而开发的。所有荧光粉样品均呈现石榴石晶体结构，$我A\overline{\mathrm{3个}}d$空间群；随着Lu ³⁺离子含量的增加，晶格逐渐收缩，具有较高的对称性和刚性。此外，在 408 nm 激发下，由于晶场分裂和斯托克斯位移， CLa _{1- x} Lu _x HA:Ce ³⁺荧光粉的青绿色发射逐渐增强，并伴有轻微的蓝移。重要的是，由于具有高对称性的高刚性结构，通过引入较小的 Lu ³⁺离子来取代较大的 La ^{3+离子，量子效率和热稳定性能得到了极大的提高。}优化的 CLa _0.5 Lu _0.5 HA:Ce ³⁺磷光体表现出强烈的青绿色发射带，具有 76.4% 的高内量子效率和 54.4% 的外量子效率。通过采用制备的 CLa _0.5 Lu _0.5 HA:Ce ³⁺青绿色荧光粉，我们成功地制造了全可见光谱 LED 器件，展示了具有极高显色指数（Ra = 98.0、R9 = 95.9 和 R12 = 94.3）和低相关性的明亮暖白光发射100 mA 驱动电流下的色温 (3497 K)。该研究不仅揭示了荧光粉材料的晶体结构演变与发光性能之间的相关性，而且为设计和开发用于高质量全可见光谱LED照明的新型高效发光材料提供了新的策略。