Bi^(3+)掺杂对CaMoO_4:Eu^(3+)荧光粉发光性质的影响

Influence of Bi^(3+) Doping on Properties of CaMoO_4:Eu^(3+) Phosphors

通过微乳液-水热法制备了CaMoO4∶Eu3+和CaMoO4∶Eu3+,Bi 3+两种红色荧光粉,并对样品进行表征,研究其结构、颗粒形貌及发光性质。结果表明,所制样品为白钨矿结构,属于四方晶系。SEM显示所制纳米粒子是四方片状结构,颗粒大小为1.5～2.5μm。光致发光(PL)光谱显示,Eu3+摩尔浓度为5%时616nm发射峰最强,对应于Eu3+的5 D0→7 F2电子偶极跃迁;随CaMoO4∶xEu3+荧光粉中Eu3+掺杂浓度变化,导致色度坐标(CIE)值由橙黄色(0.514,0.537)变化到白色(0.339,0.333);在CaMoO4∶5%Eu3+,yBi 3+红色荧光粉中,由于Bi 3+对Eu3+的敏化作用,使其发光强度增强,当Bi 3+浓度为3%时,发光强度最高;随着Bi 3+掺杂浓度的增加,CaMoO4∶5%Eu3+,yBi 3+荧光粉由橙黄色(0.497,0.347)调节到红色(0.585,0.349)。

Europium doped CaMoO4 and bismuth co-doped CaMoO4 ： Eu3＋ phosphors were prepared v/a microemulsion-hydro- thermal method. The structure, morphology and luminescence properties of samples were investigated by X-ray diffraction （XRD）, scanning electron microscopy（SEM） and fluorescence spectroscopy, respectively. The XRD patterns of as-prepared samples were in agreement with the PDF ~~ 29-0351 of CaMoO4, which indicated that the phosphor possessed tetragonal crystal structure. SEM images showed that the samples were basically flake in shape and their average size was 1.5~2.5 t^rm The criti- cal molar concentration of activator （Eu3＋ ） in CaMoO4 ： Eu3＋ was 5%, and the predominant peak of CaMoO4 ： Eua＋ located at 616 nm, corresponding to the 5Do--＊TF2 electronic dipole transition of Eu3＋. The photoluminescence color can be tuned from or- ange-yellow （0. 514, 0. 537） to white （0. 339, 0. 333） by adjusting the doping concentrations of Eu3＋ ions. To enhance the red emission intensity of Eu3＋ , Bia＋ was used to co-dope CaMoO4 ： Eu3＋ as sensitizers. When the concentration of Bi3＋ is 3 %, luminescence intensity was maximum. The chromaticity coordinates （CIE） varied from orange （0. 497, 0. 347） to red （0. 585, 0. 349） with increasing the content of Bi3＋.