Lanzhou University Researchers Develop High-Efficiency Garnet-Structured Yellow Emitting Phosphor for High-Power Laser-Driven Lighting

Wang Deyin and Wang Yuhua from Lanzhou University’s LPR lab developed a novel blue-light-excitable yellow emitter, BaLu₂(Mg₀.₆Al₂.₈Si₁.₆)O₁₂:Ce³⁺, by substituting Mg²⁺-Si⁴⁺ pairs for Al³⁺-Al³⁺ pairs in BaLu₂Al₄SiO₁₂:Ce³⁺, achieving an external quantum efficiency (EQE) of 66.2%. The substitution caused a redshift and broadening of Ce³⁺ emission, along with a reduction in thermal stability. These spectral changes are attributed to alterations in the local crystal field and positional symmetry of Ce³⁺ due to Mg²⁺-Si⁴⁺ substitution.

To evaluate the feasibility of this yellow emitter for high-power laser lighting, it was incorporated into a phosphor wheel. When excited with blue laser light at a power density of 90.7 W/mm², the yellow emitter delivered a luminous flux of 3894 lm without noticeable emission saturation. Under excitation from a blue laser diode (LD) at a power density of 25.2 W/mm², the phosphor wheel produced bright white light with a luminous flux of 1718.1 lm, a correlated color temperature of 5983 K, a color rendering index of 65.0, and chromaticity coordinates of (0.3203, 0.3631).

These findings demonstrate the significant potential of the newly synthesized yellow emitter for high-power laser-driven lighting applications.