Al2O3-TbYAG:Ce composite ceramic phosphors with balanced color rendering and lumen efficiency for high-brightness solid-state lighting

Abstract

Al₂O₃-YAG:Ce composite ceramic phosphors (CCPs) have attracted extensive attention for applications in solid-state lighting for excellent thermal performance, high light saturation thresholds, and high lumen efficiency, but the color rendering properties need to be further improved. In this work, a series of Al₂O₃-TbYAG:Ce CCPs with various Tb^3 + contents were prepared by solid-state reaction sintering. Energy transfer from Tb³⁺ to Ce³⁺ confirmed in Al₂O₃-TbYAG:Ce ceramic system. As the Tb³⁺ content increases, the color rendering index (CRI) increases and the correlated color temperature (CCT) decreases due to the effective supplementation of the red-light component. Al₂O₃-Tb_0.3Y_0.7AG:Ce CCPs possess small thermal quenching (24.7 % loss in luminescence at 225°C) and achieve an optimized CRI of up to 81.6 under LED excitation. Furthermore, these ceramic samples exhibit high lumen efficiency of 200–246 lm·W⁻¹ and suitable CCT of 4949–5117 K under 18 W·mm⁻² power density, which is of great significance for realizing high-brightness LED/LD lighting.