Phase composition design of high performance Al2O3-YAG: Ce ceramic phosphors for high-power laser lighting

The combination of laser diode (LD) chip and Al2O3-YAG: Ce composite ceramic phosphor is considered as one of the best solutions for high-power laser lighting. However, in previous studies on Al2O3-YAG: Ce composite ceramics, the effects of large-scale compositional changes on their luminous properties were rarely noticed, which hinders the understanding of the relationship between ceramic phase composition and the comprehensive properties of white LDs. In this paper, we prepared Al2O3-YAG: Ce composite ceramic phosphors with Ce3+ and Al2O3 concentrations varying widely in the range of 0.5-5 at% and 0-90 at%, respectively. An impurity phase was found in samples with high Ce3+-Al2O3 concentration by SEM images and verified to be CeAl11O18 by XRD patterns. Under high power density laser (2.3-10 W/mm2) excitation, the Ce3+ concentrations corresponding to the highest luminous efficiency of the ceramic increase from 0.5 at% to 3 at% with the introduction of Al2O3. The temperature quenching effect of ceramics is also alleviated. The CRI of ceramics first decreases and then increases with the increase of Al2O3 concentration, and the CRI of 90 at% Al2O3 samples is the highest (75.9). The results show that the introduction of Al2O3 can improve the performance of ceramics from all aspects as long as the optimal composition of Al2O3- YAG: Ce composite ceramics is selected.