Synthesis and Growth of Ce,Pr:YLuAG Crystal for LED Application

Ce,Pr:YLuAG pure phase powder was synthesized by co-precipitation method and calcined at 1450°C, which had a garnet structure. The feed rod was prepared by press forming and solid state sintering. TEM showed that the sintered rod had good crystallinity and density. Ce,Pr:YLuAG single crystal was grown by the floating zone method. The as-grown crystal was transparent with a pale yellow color, and small cracks were observed in the shoulder. The transmittance of the crystal is 81.8%, which is close to the theoretical value 84.2%. Under 460 nm excitation, Ce,Pr:YLuAG crystal shows the emission band of Ce at 530 nm and peak of Pr at 610 nm, which shows that Ce can transfer the energy to Pr. However, only Pr emission peak appears when it is excitated at 487 nm. The color coordinate is located at (0.474, 0.495) which shifts to red zone compared with commercial Ce:YAG yellow phosphor. As a result, Ce,Pr:YLuAG crystal is more suitable to fabricate white LED.