中文摘要：

采用高温固相法在弱还原气氛下制备了Ca0.955Al2Si2-xGexO8∶Eu^2＋（x=0～1.0）系列荧光粉,研究了Ge^4＋置换Si^4＋对其晶体结构和光谱特性的影响。Ge^4＋以类质同相替代CaAl2Si2O8晶格中的Si^4＋形成连续固溶体,晶胞参数a,b,c,γ和晶胞体积V随Ge^4＋置换量呈线性递增;而晶面夹角α和β随Ge^4＋置换量的增加呈线性递减。荧光激发谱为宽带,位于230 nm～420 nm,可拟合成四个峰,表观峰值位于351 nm;随着Ge^4＋置换量的增加,半高宽从114 nm减小到96 nm。发射光谱位于375 nm～600 nm,可由422 nm和458 nm两峰拟合而成,表观峰值位于426 nm;随着Ge^4＋置换量Si^4＋进入基质晶格,造成Eu-O距离变小,发光中心Eu^2＋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。

英文摘要：

A series of phosphors Ca0.955Al2Si2-x GexO8∶Eu^2＋（x=0～1.0） were prepared via solid-state reaction in weak reductive atmosphere.The lattice positions and the luminescent mechanism of Eu^2＋ in the host were discussed;the effects of Ge^4＋-substitution on the host lattice and spectral properties were also investigated.The results showed that complete solid solutions formed in the whole range of x = 0～1.0 while Ge^4＋ entered CaAl2Si2O8 lattice and substituted Si^4＋.The lattice parameters（a,b,c,γ） and unit cell volume of phosphors Ca0.955Al2Si2-xGexO8∶Eu^2＋（x=0～1.0） increased linearly and the lattice parameters（α,β） decreased linearly as Ge^4＋ content increased in the phosphors.A broad excitation spectrum consists of four excitation bands,which locate between 230 nm and 420 nm,the maximum emission wavelength of which is at 351 nm.The FWHM of the apparent excitation peak narrowed from 114nm to 96nm.The broad and asymmetric emission spectrum among 375 nm and 600 nm and apparent peak is at 426 nm,which can be fitted by two peaks at 422 nm and 458 nm.The distance of Eu and O became shorted due to Si^4＋ is replaced by Ge^4＋.The crystal field of the emitting center Eu^2＋ location is enhanced,The splitting of 5d orbital levels is increased and the lowest emission level is expanded to lower,two fitted peaks are red shifted.