无压烧结制备Y_(2)MgAl_(4)SiO_(12)∶Ce^(3+)荧光陶瓷及光学性能

Preparation and Optical Properties of Y_(2)MgAl_(4)SiO_(12)∶Ce^(3+)Fluorescent Ceramics by Pressureless Sintering

Y_(3)Al_(5)O_(12)∶Ce^(3+)荧光粉是目前白光LED的主要发光材料,但在使用时存在封装树脂因散热不佳而发生老化等问题。本文采用无压烧结制备了Y_(2)MgAl_(4)SiO_(12)∶Ce^(3+)透明陶瓷荧光体,用于替代荧光粉体和调控发光性能。首先通过化学共沉淀法制备前驱体粉体,经高温煅烧后采用冷等静压成型,最后在马弗炉中1 600℃煅烧制得透明荧光陶瓷。研究了Ce^(3+)掺杂浓度和样品厚度对材料性能的影响,其中掺杂量为0.5%的样品在800 nm处具有56%的透过率,在450 K下发光强度仍能保持室温强度的84%。与蓝光芯片组装成器件测试表明,荧光陶瓷在蓝光LEDs/LDs的激发下发出白光,其CIE色度坐标分别为(0.307 6,0.332 9)和(0.308 0,0.331 6),光效分别为62.6 lm/W和146.3 lm/W。研究结果表明,YMAS∶Ce荧光陶瓷可应用于白光LEDs/LDs领域。

Y_(3)Al_(5)O_(12)∶Ce^(3+)(YAG∶Ce)phosphor is the main luminous material for white light emitting diode(LED)or laser diode(LD)at present,but it has some drawbacks such as aging due to poor heat dissipation.In this paper,Y_(2)MgAl_(4)SiO_(12)∶Ce^(3+)(YMAS∶Ce)transparent ceramic fluorophores were prepared by simple pressureless sintering,which can replace traditional fluorescent powder and regulate luminescence performance.The precursor powder was prepared by chemical coprecipitation method and calcined at high temperature.Green body disks were formed by cold isostatic pressing using the sintered powder.Finally,transparent fluorescent ceramics were prepared by calcin⁃ing the disks at 1600℃ temperature in a muffle furnace.The effect of Ce^(3+) doping concentration and sample thick⁃ness on the properties of the material was studied.The sample doped 0.5% of Ce^(3+)possessed 56% transmittance at 800 nm,and its luminescence intensity at 450 K is still maintain 84% of that at room temperature.The device com⁃bined with the fluorescent ceramics can emit white light under the excitation of blue LEDs/LDs.The corresponding CIE chromaticity coordinates were(0.3076,0.3329)and(0.3080,0.3316),and the luminous efficiency was 62.6 lm/W and 146.3 lm/W,respectively.The results show that YMAS∶Ce fluorescent ceramics can be applied to white LEDs/LDs.