AlO-YAG:Ce composite ceramics for high-brightness lighting.

LD chips, combined with phosphor converters, are considered as optimum candidates for high brightness lighting. In this work, AlO-YAG:Ce composite ceramics were prepared as the phosphor converters. The sintering temperature and the sintering additives were optimized to obtain the highest quantum efficiency. The effect of the molar ratio of AlO to YAG:Ce on the performance of the ceramics that were excited by the LD chips was studied. The results show that the light extraction efficiency from the ceramic surfaces increases with the increasing molar ratio of AlO to YAG:Ce. Moreover, the improved thermal conductivity caused the ceramics with higher molar ratio of AlO to YAG:Ce show alleviative luminescence saturation and improved reliability.