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

A novel single-phased white light emitting phosphor, Ca2(La1−xEux)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 5D0 → 7FJ (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 5D3 → 7FJ (J = 1, 2, 3), 5D2 → 7FJ (J = 0, 1, 2, 3), 5D1 → 7FJ (J = 1,2,3), and 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions. The higher level 5DJ (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 Ca2(La1−xEux)TaO6 phosphors are 5D3,2,1,0 → 7FJ emissions, whereas the dominant transitions are 5D0 → 7FJ emissions for higher Eu3+ ion concentrations. The chromaticity coordinate of the Ca2(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.