白光二极管用Ba_3MgSi_2O_8基质发光材料的溶胶雾化-微波烧成与光谱性质  

Sol Spray-microwave Cancining and Luminescence Properties of Ba_3MgSi_2O_8 Hosted Phosphors for White Light Emitting Diodes

作　　者：李雪征[1] 王达健[1,2,3] 顾铁成 毛智勇[3] 刘艳花[3] 

机构地区：[1]天津理工大学显示材料与光电器件教育部重点实验室,天津300384 [2]天津光电子材料与器件重点实验室,天津300384 [3]天津理工大学材料物理研究所,天津300384

出　　处：《发光学报》2008年第6期989-995,共7页Chinese Journal of Luminescence

基　　金：天津市科委资助项目(06YFJMJC02300;06TXTJJC14602)

摘　　要：分别采用溶胶雾化-微波烧成工艺和高温固相法制备了用于白光发光二极管的Ba3MgSi2O8∶Eu,Mn,Al荧光粉。溶胶雾化-微波烧成两步法制备的样品物相纯度和结晶度都比较高,具有中心位置437,500,608nm的三色发射带。在375nm紫外光激发下,发光的色坐标为x=0.3253,y=0.2134,相关色温7391K,可得到预期的白光发射。其中蓝、绿两个发射带分别来自于Ba3MgSi2O8和Ba2SiO4晶格中Ba2+格位的替位原子Eu2+的5d-4f跃迁,红光发射带源于Ba3MgSi2O8中Mn2+的4T-6A跃迁发射。红光的激发谱与蓝光的激发谱几乎重合,可以确定在Ba3MgSi2O8∶Eu,Mn,Al发光过程中存在着从蓝光发射中心到红光发射中心的能量传递。但是,与通常的共振能量传递模型不同,蓝光发射谱与红光激发谱之间并没有明显的光谱重叠。相比之下,高温固相法样品没有观察到红光发射,这一方面是由于生成的Ba2SiO4中杂相较多,激发光很大一部分被Ba2SiO4晶格中的Eu2+绿光发光中心吸收,传递到Mn2+红光发光中心的能量减少;另一方面与固相法中Mn2+在Ba3MgSi2O8晶格中掺杂困难有关。Phosphors Ba3MgSi2O8： Eu, Mn, Al in application of white light emitting diodes （ WLEDs ） have been synthesized by sol spray-microwave calcining process, as well as solid state reaction, respectively. Sampies prepared by sol spray-microwave calcining method with higher purity and better crystallinity according to XRD results, show three emission bands locating at 437,500 and 608 nm, which give the expected white light with color coordinates x =0. 325 3 ,y =0.213 4, correlated color temperature （CCT） 7 391 K under excitation of 375 nm ultraviolet. Samples from solid state reaction, however, show only the former two peaks under the same excitation, and take on bluish green with color coordinates x = 0.221 0, y = 0.373 0. Mechanisms of white light emission in Ba3MgSi2O8： Eu, Mn, Al samples have been studied. The blue and green emissions are ascribed to 4f^65d^1-4f^7 transition of Eu^2＋ in substition of Ba^2＋ in Ba3MgSi2O8 and Ba2SiO4 lattice, respectively. The red one, originated from 4T-6A transition of Mn^2＋ in place of Mg^2＋ in Ba3MgSi2O8, shows an excitation spectrum similar to that of the blue emission. Enegy transfer from Eu^2＋ to Mn^2＋ is confirmed based on the similarity of excitation spectra and longer decay time of red emission than that of blue one. However, the fluorescent spectra do not agree with the theoretical model of resonant energy transfer for the little overlapping and between blue excitation and red emission spectra. This phenomenon may relate to energy transfer of excitons. Nevertheless, visible red emission doesn＇t occur in samples from solid state reaction, in which more impurity phase Ba2SiO4 exists. It can be attributed to the absorption of a large part of excitation energy by Eu^2＋ in Ba2SiO4 lattice. And the difficuhy in doping Mn^2＋ into BaaMgSi2O8 lattice involving in the process itself may account for it, to some content at least. In summay, remarkable advantages of sol spray-microwave calcining method over solid state reaction can be concluded as time-

关 键 词：Ba3MgSi2O8:Eu Mn Al发光粉 微波烧成 喷雾干燥 能量传递 白光二极管 

分 类 号：O482.31[理学—固体物理]