稀土铈掺杂浓度对钇铝石榴石(Y_(3-x)Al_5O_(12)∶Ce_x)粉体性能的影响研究

Performance of Ce-Doped Yttrium Aluminum Garnet (Y_(3-x)Al_5O_(12)∶Ce_x) Powder with Various Ce Content

实验用共沉淀法制备出不同铈掺杂浓度的钇铝石榴石(Y3-xAl5O12∶Cex)粉体。用综合热分析仪、X射线衍射仪、透射电镜、荧光光度计等测试手段对Y3-xAl5O12∶Cex前驱体及煅烧后的粉体进行了晶体结构、形貌和发光性能等方面的表征。研究表明:合成石榴石粉体的最佳煅烧温度应该在1050℃以上,用此方法可得到分散性好,形状规则且粒径为50 nm的石榴石粉体。随着Ce掺杂量的增加,样品的结构没有发生显著的变化,均为YAG相。只是衍射强度随着x的增加而增强。当x=0.20时,出现了CeO2相。Y3-xAl5O12∶Cex的激发光谱为双峰结构,在近紫外340 nm处有一激发峰,在可见光区有一最大激发峰在460 nm处。Ce3+的4f能级由于自旋耦合而劈裂为两个光谱支项2F7/2和2F5/2,其中2F5/2为基谱项。340 nm的激发峰对应2F5/2→5d的跃迁,460 nm的激发峰属于2F7/2→5d的跃迁。发射光谱都由一组尖峰组成,发射峰对应的波长在530 nm处。

Different concentration Ce-doped Y3Al5O12 were prepared by the co-precipitation method. The precursor and calcined powders were characterized by the thermogravimetry and differential thermal analysis, X-ray diffraction, transmission electron microscope, spectroph otometer. The results showed that the best calcining temperature to synthesize garnet powder should be 1050 ℃ above and well dispersive, regular shape garnets powders with an average particle size of about 50 nm were obtained. With Ce content increasing, crystal structure of the sample never significantly change, all were the YAG phase. The excitation spectrum of Y3-xAl5O12： Cex had two peaks. It had an ultraviolet stimulate peak in the nearly 340 nm and maximum stimulate peak in visible spectrum area 460 nm. The 4f energy-level of Ce^3＋ was split into two spectrums of ^2F7/2 and ^2F5/2 due to spin-coupling. ^2F5/2 was the based spectrum. The excitation peaks at 340 nm belonged to ^2F5/2→5d transition and 460 nm was ^2F7/2→5d transition. The emission spectrum consisted of peaks and their diffraction peak wavelength was at the 530 nm.