Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+)荧光粉的形貌演变与光学性能研究

Morphology evolution and optical properties of Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+) phosphors

采用熔盐法制备了立方块状的Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+)粉体,通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)及荧光光谱分析(PL)对样品进行表征.通过改变保温时间和熔盐与原料比例研究晶体形貌的演变.当NaCl熔盐质量与反应物总质量的比为7∶1,反应温度为1 200℃时反应6h合成的Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+)粉体颗粒形貌最规整、尺寸最均匀且颗粒分散性最好.Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+)颗粒生长遵循Oswald熟化机制,颗粒的生长过程表现为小颗粒溶解并在大颗粒表面析出,从而大颗粒长大.立方块状的Na_(0.5)Sr_(0.25)NbO_3:0.03Eu^(3+)粉体有位于396nm和466nm处两个特征强激发峰,在619nm处的发射光谱表明有强烈的红光发射.利用Judd-Ofelt理论分析验证了Eu^(3+)处于Na_(0.5)Sr_(0.25)NbO_3晶体环境的不对称位置,其最高量子效率可达61.61%,是潜在可被近紫外和蓝光芯片激发的红色荧光粉.

The cubic like Na0.5Sr0.25NbO3：0.03Eu3＋ powder was prepared via the molten salt method. The samples were characterized by X ray diffraction （XRD） , scanning electron mi croscopy （SEM） and flu was studied by changing most regular, the most NbO3 ： 0.03Eu3＋ powder orescence spectroscopy （PL）. The evolution of crystal morphology the holding time and the ratio of molten salt to raw material. The uniform in size, and the better particle disp was synthesized at the reaction temperature ersibilit y of Na0. s Sr0. 8 ℃ for 6 hours,when the ratio of NaCl molten salt mass to total reactant mass is 7 ： 1. The growth of Na0.5Sr0.25NbO3：0.03Eu3＋ particles followed the Oswald ripening mechanism, and the growth process of the particles showed up as small particles dissolved and precipitated on the surface of large particles, which resulted in the growth of large particles. The cubic like Na0.5Sr0.25NbO3：0.03Eu3＋ powder have two characteristic strong excitation peaks at 396 nm and 466nm. The emission spectrum at 619 nm shows strong red emission. By the Judd Ofelt theo ry,it was verified that the Eu3＋ ion is in the asymmetrical position of the Na0. 5 Sr0. 25 NbO3 crystal environment,and the highest quantum efficiency can reach 61.61% ,which is demon strated that the red phosphor can potentially be excited by near ultraviolet and blue chips.