MBiO_2Cl(M=Ca,Sr,Ba)材料的合成、能带计算及发光性能研究  

Synthesis,electronic structure and optical properties of MBiO_2Cl(M=Ca,Sr,Ba)

作　　者：李会亮[1] 袁军林[1] 王小军[1] 赵景泰[1] 张志军[1] 杨昕昕[1] 

机构地区：[1]中国科学院上海硅酸盐研究所,上海200050

出　　处：《物理学报》2008年第12期7878-7884,共7页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:50332050);国家重点基础研究发展规划(批准号:2007CB936704);中国科学院国际合作计划资助的课题~~

摘　　要：采用固相合成方法制备出CaBiO2Cl,SrBiO2Cl和BaBiO2Cl粉体,研究了该Sillen系列铋基氧卤化合物的光学带隙、电子结构及发光性能.基于密度泛函理论计算表明,SrBiO2Cl和BaBiO2Cl均为直接带隙半导体材料,与吸收光谱实验结果相符合.在X射线和紫外光激发下三者均具有宽的可见光发射带(400—550nm),尤其是BaBiO2Cl粉体的光输出强度约为Bi4Ge3O12(BGO)粉体光输出强度的1.4倍,并且具有更短的衰减时间,发光衰减时间的主要部分为100ns(22%)和300ns(41%),而BGO粉体的主要衰减时间为300ns(75%).实验分析表明,该化合物发光性能与晶体结构中Bi—O(Cl)键长及碱土金属离子的半径相关.同时BaBiO2Cl具有较大的密度(6.98g/cm3),因此它是一种具有潜在应用价值的闪烁材料.The absorption, electronic structure and luminescence spectrum of three Sillen bismuth oxyhalides, CaBiO2 Cl, SrBiO2 Cl and BaBiO2 Cl, are reported and analyzed. The calculated electronic structure by the density functional theory shows that both SrBiO2Cl and BaBiO2Cl are semiconductors with direct band gap, which are consistent with the results of ultraviolet （UV）-vis diffuse reflectance experiment. The X-ray and UV excited luminescent spectra show a broad emission band extending from 400 to 550 nm at room temperature. The light yield of BaBiO2 Cl powders is about 1.4 times that of Bi4 Ge3 O12 （BGO） powders at room temperature under X-ray excitation, and BaBiO2 Cl powders have shorter decay times of 100 ns （22%）, 300 ns （41% ） and 600 ns （37%）, compared with those of the BGO powders. The luminescence properties show a correlation between Bi--O（Cl） distance and radius of M^2＋ ions. Considering that the density of BaBiO2Cl is 6.98 g/cm^3, it may be a potential practical scintillator.

关 键 词：光致发光 电子结构 Sillen化合物 

分 类 号：O482.31[理学—固体物理]