焙烧温度和掺杂浓度对Ca_(1-x)Sm_xWO_4发光性能的影响

Effects of Doped Concentration and Calcination Temperature on Luminescence Properties of Ca_(1-x)Sm_xWO_4 Phosphors

采用水热法制备了不同Sm^(3+)掺杂量和不同焙烧温度的CaWO_4:Sm^(3+)系列荧光粉。用X射线衍射仪(XRD)、扫描电镜(SEM and EDS)、荧光分光光度计(FL)、傅里叶变换红外光谱仪(FIIR)和HORIBA Fluoromax-4仪等手段对样品的组成、结构、形貌、发光性质和量子效率进行分析和表征。分析结果表明:所得产物都为白钨矿结构。在405 nm近紫外光激发下,产物的发射光谱都有3个主发射峰组成,分别位于566、606和650 nm处,归属于Sm3+的4G5/2→6HJ/2(J=5,7,9)跃迁。随着Sm^(3+)的物质的量分数的增加,样品发光强度先增强后减弱,当Sm^(3+)的物质的量分数为1%时发光强度达到最高。对实验数据进行分析确定了钐离子间的能量传递类型为离子交换作用;并计算了能量传递的临界距离为2.46 nm。

The Ca1-xSmxWO4 phosphors with different doping concentrations and different sintered temperatures were synthesized by hydrothermal method. The phase structure,morphology, luminescent properties and quantum efficiency of the as-synthesized samples were characterized by X-ray diffraction,fourier transform infrared spectroscopy, scanning electron microscope, fluorescence spectrophotometer respectively and Fluoromax-4. The results showed that all the phases were indexed to scheelite structure. The emission spectra of Ca1-xSmxWO4 phosphors exhibit three main peaks assigned to the 4G5/2→6HJ /2（J=5,7,9） transitions of Sm3＋under 405 nm excited radiation, the dominating emission peaks at 566, 606, 650 nm. The luminescence intensity firstly increases with increasing of Sm3＋mole fraction, and then decreases. Experiments show that the best Sm3＋ doping concentration is1%. The energy transfer type between Sm3＋ ions was determined to be the exchange interaction and the critical energy transfer distance（Dc） was calculated to be 2.46 nm.