Keywords: 
• 能量传递 /
• 红色荧光粉 /
• 温度依赖 /
• CaWO4:Eu3+

Abstract: The pure CaWO4 and 1%Eu3+doped CaWO4 phosphors are successfully prepared by the conventional solid state reaction method. The photoluminescence (PL) spectra, decay cures, and time-resolved PL spectra are measured at depend on different temperatures. Fluorescence spectra at room temperature (300 K) and low temperature (10 K) show that these two samples each have a broad band at about 430 nm, originating from the WO2?4 groups under 240 nm excitation, while the CaWO4:Eu3+sample exhibits the characteristic emission of Eu3+ corresponding to 5D0→ 7F1,2,3,4 transitions due to the absorbed energy transfer from WO2?4 groups to Eu3+ ions. And the red light at 616 nm of CaWO4:Eu3+can be excited efficiently by UV (395 nm) and blue (465 nm) light. The decay curves at 300 K illustrate that the lifetime of WO2?4 group in pure CaWO4 is about 8.85 μs but is shortened to 6.27 μs after Eu3+ions have been doped, which is a further good evidence for demonstrating the existence of WO2?4 -Eu3+energy transfer process. The energy transfer efficiency (ηET) and rate (ωET) between WO2?4 and Eu3+in CaWO4:1%Eu3+are 29.2%and 4.65 × 104 s?1 respectively, when T =300 K. The energy transfer process is studied in detail by the time-resolved PL spectra, and the lifetime for the appearance of Eu3+ emission in CaWO4 decreases monotonically as temperature increases from 10 K to 300 K. The temperature dependence of luminescence decay time is performed and the results indicated that the lifetime of Eu3+increases in a temperature range of 10-50 K, when the temperature is more than 50 K, thermal quenching of Eu3+ begins and the lifetime is shortened. However, the lifetime of WO2?4 reduces constantly with the increase of temperature.