Co-substitution in Ca1-xYxAl12-xMgxO19 phosphors: local structure evolution, photoluminescence tuning and application for plant growth LEDs

Herein, Mn⁴⁺-activated Ca_1−xY_xAl_12−xMg_xO₁₉ (x = 0–0.50) solid solutions were prepared using a conventional high-temperature solid-state reaction. Crystal structure transformation via chemical co-substitution of Y³⁺/Mg²⁺ for Ca²⁺/Al³⁺ was investigated in detail. The optical properties of Ca_1−xY_xAl_12−xMg_xO₁₉ (x = 0–0.50) have been reported for the first time using a combination of techniques including structural refinement and luminescence measurements. Co-doping of Mg and Y cations within the CaAl₁₂O₁₉ host in a controlled manner resulted in the as-prepared samples with red/far-red ratio-tunable luminescence properties. The emission bands well-matched with the absorption band of phytochrome. Interestingly, enhanced Mn⁴⁺ luminescence can be obtained upon the addition of Mg²⁺ and Y³⁺. Unexpectedly, the quantum yields exhibit a slight change when x is in the range from 0.05 to 0.40; this indicates that these solid solutions have significant potential as lighting systems for plant growth.