A novel single-phased white light emitting phosphor of Eu3+ ions-doped Ca2LaTaO6

A novel single-phased white light emitting phosphor, Ca-2(La1-x,Eu-x)TaO6 (x = 0.001-0.7), was synthesized using a vibrating milled solid state reaction. The results indicate that the emission spectra of Ca2LaTaO6:Eu3+ samples exhibit a series of shaped peaks assigned to the D-5(0)-> F-7(J) (J = 0, 1, 2, 3, 4) transitions under an excitation of 395 nm. The characteristic peaks of Eu3+ ion intra-4f transitions from excited states to lower levels include D-5(3) -> F-7(J) (J= 1, 2, 3), D-5(2) (J= 0, 1, 2, 3), D-5(1) F-7(J) (J = 1,2,3), and D-5(0) -> F-7(J) (J = 0, 1, 2, 3, 4) transitions. The higher level D-5(J) (J= 1, 2, 3) emission depends on the concentration of Eu3+ ions. The emission spectra shows a completely different ratio between the 5D3,2,1 blue-green emission and 5D0 red emission for lower and higher Eu3+ concentrations. For lower Eu3+ ion concentrations, the dominant transition of Ca-2(La1-xEux)TaO6 phosphors are D-5(3),(2),(1,0) -> F-7(J) emissions, whereas the dominant transitions are D-5(0) -> F-7(1) emissions for higher Eu3+ ion concentrations. The chromaticity coordinate of the Ca-2(La1-xEux)TaO6 phosphor varies with the Eu3+-doped concentrations from white, to reddish orange, and red. Thus, this type of phosphor may be potentially applicable as a white light emitting phosphor for ultraviolet light-emitting diodes. (C) 2013 Elsevier B.V. All rights reserved.