Ce,Pr:YLuAG原料合成、晶体生长及LED应用

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

采用共沉淀法合成了Ce,Pr:YLu AG粉末,在1450℃下煅烧可获得石榴石结构纯相。经过压制成型、固相烧结等工艺制备了多晶料棒,TEM显示二次烧结获得的料棒具有良好的结晶性。采用光学浮区法生长了Ce,Pr:YLu AG晶体。晶体通体透明,呈浅黄色,肩部有少量裂纹。透过率达到81.8%,接近于理论值84.2%。晶体在460 nm波长激发下呈现530 nm发射带和610 nm发射峰,分别对应Ce3+和Pr3+的特征发射,表明Ce3+可以向Pr3+进行能量转移;在487 nm激发下晶体仅出现Pr3+离子的特征发射峰。Ce,Pr:YLu AG晶体色坐标为(0.474,0.495),比商用Ce:YAG荧光粉更靠近红光区域,可以弥补现有荧光粉不足,更适合制造白光LED。

Ce,Pr：YLu AG 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：YLu AG 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：YLu AG crystal shows the emission band of Ce3＋ at 530 nm and peak of Pr3＋ at 610 nm, which shows that Ce3＋ can transfer the energy to Pr3＋. However, only Pr3＋ 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：YLu AG crystal is more suitable to fabricate white LED.