| As a favorite substance in inorgnic compounds, tungstate was extnesively invested because of its wide field of application.Using hydrothermal method, the rare earths co-doped CWO nanometer luminescent materials were prepared which selected cadmium tungstate (CWO) as matrix material, Yb3+ions were used as sensitizer and Er3+-Tm3+ions were used as activator. CWO:Yb3+-Tm3+, CWO:Yb3+-Er3+and CWO:Yb3+-Tm3+-Er3+were prepared, respectively.The samples were studied by X-ray diffraction analysis (XRJD) and field emission scanning electron microscope (ESEM). The results showed that rare earths co-doped CWO nano-crystals was monoclinic system with its particle size ranging from30nm to90nm. Using980nm semiconductor laser as pump light source, the emission spectra were measured by spectrophotometer and the results were as follows:1. CWO:Yb3+/Tm3+nano-crystals had a strong blue emission peak with its peak at481nmwhich was corresponding to the1G4'3H6transition of Tm3+ions.The maximum luminous intensity was achieved when the mole concentration ratio of Yb3+/Tm3+was10:1and the concentration of Tm3+ions was2mol%.2. CWO:Yb3+/Er3+nano-crystals had three obvious peaks at528nm,552nm and660nm which were corresponding to the2H11/2'4I15/2,4S3/2'4I15/2and4F9/2'4I15/2transitions of Er3+ions, respectively. When the mole concentration ratio of Yb3+/Er3+was5:1and the concentration of Er3+was0.5mol%,the strongest emission peaks were achieved.3. CWO:Yb3+/Er3+/Tm3+nano-crystals had four obvious peaks at482nm、530nn、547nm and662nm,respectively. The blue peak at482nm was formed because of the4F7/2'4I15/2transition of Er3+ions and the1G4'3H6transition of Tm3+ions. The green peak at525nm and547nm were corresponding to the4S3/2'4I15/2transition of Er3+ions. The red peak at662nm was corresponding to4F9/2'4I15/2transition of Er3+ions. And the strongest luminous intensity was observed when the concentration of Er3+ions was0.6mol%and the mole concentration ratio of Yb3+/Er3+/Tm3+was7:1:1. |
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