【摘要】 采用水热法制备CdWO4∶Yb3+,Ho3+纳米晶,运用X射线衍射、扫描电镜和光谱分析对制备样品的结构和发光性能进行了表征。结果表明:CdWO4∶Yb3+,Ho3+为单斜晶系,平均晶粒尺寸约为29.782 7 nm。用980 nm激光激发样品获得了发射光谱,位于552 nm和659 nm的发射峰分别对应于Ho3+离子的5F45S2→5I8和5F5→5I8的跃迁。根据泵浦功率和发光强度之间的双对数关系可知,552 nm和659 nm的发射均属于双光子过程。稀土离子的浓度对样品的发光强度的影响较大,结果表明:当Yb3+∶Ho3+离子的量比为5∶1且Ho3+摩尔分数为1.5%时,CdWO4∶Yb3+,Ho3+纳米晶的上转换发光强度最大。更多还原

【Abstract】 Yb3 +,Ho3 +ions co-doped CdWO 4 nano-crystals were synthesized by hydrothermal method.The characterization and structure of the samples were measured by X-ray powder diffractions(XRD),field emission scanning electron microscope(ESEM) and fluorescence spectrophotometer.The results show that CdWO 4 ∶ Yb3 +,Ho3 +is monoclinic crystal system with the mean size of 29.782 7 nm.The emission spectra were obtained when the samples were excited by 980 nm semiconductor laser.The green(552 nm) and red(659 nm) emission peaks are obviously observed,which are corresponding to the5F 4 5S 2 →5I 8 and5F 5 →5I 8 transitions of Ho3 +ions.According to the relationship between pump power and luminescence intensity,the green and red peaks can be due to the double-photons absorption processes.The concentration of the rare earths could influence the luminescence intensity.The strongest peak was obtained when the mole fraction of Ho3 +is 1.5% and the ratio of n(Yb3 +) ∶ n(Ho3 +) =5∶ 1.更多还原