Temperature-dependent Photoluminescence Properties of Eu2+-doped CaMgSi2O6 Phosphors

The solid-state reaction method was used to synthesize 0.025Eu2+-doped CaMgSi2O6 (Eu-CaMgSi2O6) powder in the reduction atmosphere of 5% H2 + 95% N2 at 1300oC with a duration of 4 h. The reduction atmosphere was removed when the temperature was down to 800oC. The XRD pattern showed that only the CaMgSi2O6 phase was observed in synthesized 0.025Eu2+-doped CaMgSi2O6 powder. Room-temperature photoluminescence excitation (PLE) and photoluminescence (PL) spectra of Eu-CaMgSi2O6 phosphors were recorded by using the Hitachi F-4500 fluorescence spectrophotometer at wavelength ranges of 200–430 and 350–600 nm, respectively. A new important finding is that the synthesized Eu-CaMgSi2O6 phosphor has three important PLE wavelengths. Therefore, Eu-CaMgSi2O6 phosphors are measured from 25oC (room temperature) to 200oC under three different PLE wavelengths to find the effect of temperature on the variations of maximum photoluminescence intensities (PLmax). All the PL spectra show that only one emission band with a central wavelength of 449 nm is found, which is independent of the PLE wavelengths and is caused by the transition of 4f7 → 4f65d1. Another important finding is that the different PLE wavelengths have an apparent effect on the PLmax value of the Eu-CaMgSi2O6 phosphor. Finally, the decay-time curves of Eu-CaMgSi2O6 phosphor under three PLE wavelengths are also investigated.