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, 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 3+ at 530 nm and peak of Pr 3+ at 610 nm, which shows that Ce 3+ can transfer the energy to Pr 3+ . However, only Pr 3+ 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.