Effects of fluxes on preparation and luminescence properties of CaSi2O2N2:Eu2+ phosphors

The effect of fluxes on CaSi 2 O 2 N 2 :Eu 2+ phosphors obtained via conventional solid-state reaction at atmospheric pressure is systematically investigated. The photoluminescence excitation and emission spectra of CaSi 2 O 2 N 2 :Eu 2+ phosphors containing fluxes are investigated and discussed in detail. A strong emission band is observed peaked at 548 nm originating from transitions between 4f 6 5d 1 emitting state and 4f 7 ground state of Eu 2+ under near ultraviolet light (398 nm) excitation. The results show that the best synthesis temperature of the sample is 1450 °C with the absence of combustion aid to obtain single phase of CaSi 2 O 2 N 2 :Eu 2+ . After adding BaF 2 , NH 4 Cl and Na 2 CO 3, single phase samples of CaSi 2 O 2 N 2 :Eu 2+ with well-defined morphology can be successfully prepared at a temperature as low as 1400 °C. It is interesting that in the samples prepared under the assistance of BaF 2 fluxes, the luminous intensity of Eu 2+ is much higher than in the absence of fluxes.