[Luminescence investigation of Na(z)Ca(1-x-2y-z)Bi(y)MoO4 : Eu(x+y)3+, red phosphors].

A series of red phosphors with the composition Na(z)Ca(1-x-2y-z), Bi(y) MoO4 : Eu(x+y)3+ (y, z = 0, x = 0.24, 0.26, 0.30, 0.34, 0.38; x = 0.30, y = 0.01, 0.02, 0.03, 0.03, 0.05, 0.06, 0.07; x = 0.30, y = 0.04, z = 0.38) were prepared via traditional solid-state method. The crystal structures of the obtained phosphors were identified by X-ray powder diffraction (XRD) method. The photoluminescence properties of the samples were characterized by fluorescence spectrophotometer. The results indicated that the concentration of Eu3+ single doped Ca(1-x) MoO4 : Eu3+ with the maximum luminescence intensity was found to be 0.30 (namely, Ca0.70 MoO4 : Eu(0.30)3+); the photoluminescence properties with different ratio of Bi3+/Eu3+ codoped Ca0.70-2y Bi(y) MoO4 : Eu(0.30+y)3+, were also investigated, and the results showed that the charge band (CTB) reached the maximum value when the y value was equal to 0.03; for the characteristic excitation peaks of Eu3+, however, the intensity of the excitation spectral line locating at 393 nm was stronger than that at 464 nm when y < 0.03, while the intensity at 464 nm was greater than that at 393 nm when y > or = 0.03; the intensity of excitation peaks locating at 393 and 464 nm respectively both reached the maximum intensity when the y value was 0.04. The relative intensity of the excitation and emission of the above phosphor was enhanced greatly when Na2CO3 acting as charge compensation was added. The above results showed that the relative intensity between 393 and 464 nm could be changed by adjusting the ratio of Bi3+ /Eu3+ codoping concentrations.