Effect of flux on the composition and luminescent properties of Ca0.68Mg0.2SiO3:0.12Eu3+ red phosphor

Ca0.68Mg0.2SiO3:0.12Eu3+ red-emitting phosphor was synthesized via one-step calcination process of the precursor prepared by chemical coprecipitation with different fluxes. Then X-ray diffraction and fluorescence spectrophotometry were adopted to investigate the structure and luminescent properties of Ca0.68Mg0.2SiO3:0.12Eu3+. The results indicated that adding fluxes increased the crystalline significantly while the phase composition of samples was not changed. Furthermore, the fluxes improved the intensity of emission peak and the quantum efficiency greatly. With the concentration of flux (Li2CO3 or K2CO3) increasing, the emission intensity of Ca0.68Mg0.2SiO3:0.12Eu3+ firstly increased and then decreased. Meanwhile, red-shift phenomenon was observed in the emission spectra. The optimal adding fraction of Li2CO3 and K2CO3 was 6% and 5% respectively, and the luminous intensity of samples calcined with the optimum adding amount of Li2CO3, K2CO3 is 42 and 48 times that of the samples without flux. K2CO3 showed a better effect on improving the emission intensity of the phosphors than Li2CO3.