白光LED用Ba_(0.955)Al_2Si_(2-x)Ge_xO_8∶Eu^(2+)荧光粉的晶体结构和光谱特性研究  

Crystal Structure and luminescent properties of Ba_(0.955)Al_2Si_(2-x)Ge_xO_8E:u^(2+) phosphors for white LED

作　　者：王飞[1] 田一光[2] 张乔[2] 

机构地区：[1]安徽三联学院实验中心,安徽合肥230601 [2]温州大学化学与材料工程学院,浙江温州325035

出　　处：《光电子．激光》2013年第12期2349-2354,共6页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(20771086);安徽三联学院科研(2013Z001)资助项目

摘　　要：采用高温固相法在弱还原气氛下制备了Ba0.955Al2Si2-x Gex O8∶Eu2+(x=0.0~1.0)系列荧光粉,研究了Ge4+置换Si 4+对其晶体结构和光谱特性的影响。Ge4+以类质同相替代Ba长石(BaAl2Si2O8)晶格中的Si 4+形成连续固溶体,晶胞参数a、b、c、β和晶胞体积V随Ge4+置换量呈线性递增。荧光激发谱为宽带,位于230~400nm处,可拟合成4个峰,最大峰值位于332nm;随着Ge4+置换量的增加,半高宽(FWHM)从93nm减小到80nm。发射光谱位于375~600nm,可由422nm和456nm两峰拟合而成,最大峰值位于434nm;随着Ge4+置换量Si 4+进入基质晶格,造成Eu-O距离变小,发光中心Eu2+所处晶体场增强,5d轨道能级分裂变大,最低发射能级下移,两拟合峰均线性红移。A series of phosphors Ba0. 955 Al2 Si2-x GexO8 ：Eu2＋ （x=0. 0-1.0） were prepared via solidstate reaction in weak reductive atmosphere. The lattice positions and the luminescent mechanism of Eu^2＋ in the host are discussed. The effects of Ge^4＋-substitution on the host lattice and spectral properties are also investigated. The results show that complete solid solution is formed in the whole range of x = 0.0-1.0 while Ge^4＋ enters BaAl2 Si2O8 lattice and substitute Si^4＋. The lattice parameters （a,b, c,β） and unit cell volume of phosphors Ba0.955 Al2Si2-x GexO8 ： Eu^2＋ （x=0. 0-1.0） increase linearly as Ge^4＋ content increases in the phosphors. A broad excitation spectrum consists of four excitation bands, which locate between 230 nm and 400 nm, and the maximum emission wavelength is at 332 nm. The FWHM of the apparent excitation peak is narrowed from 93 nm to 80 nm. The broad and asymmetric emission spectrum is between 375 nm and 600 nm and apparent peak is at 434 nm,which can be fitted by two peaks at 422 nm and 456 nm. The distance between Eu and O is shortened due to Si^4＋ is replaced by Ge^4＋. The crystal field of the emitting center Eu^2＋ is enhanced. The splitting of 5d orbital levels is enhanced and the lowest emission level is expanded to lower region,and two fitted peaks are red shifted.

关 键 词：硅酸盐 Ba长石(BaAl2Si2O8) Ge置换 EU^2+ 

分 类 号：O614.371[理学—无机化学]