The self-reduction synthesis and luminescent properties of Eu 2+ /Eu 3+ activated BaZr x Si 3 O 7+2x phosphors with white light emission for white light-emitting diodes.

The BaZrx Si3 O7+2x :Eu2+ /Eu3+ (2%, molar ratio) phosphors were prepared with adding different amounts of zirconium dioxide (ZrO2 ) (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) by a self-reduction method under air conditions. X-ray diffraction, photoluminescence properties, thermal quenching properties and luminescent lifetimes of the prepared samples were systematically analyzed. In BaZrx Si3 O7+2x :Eu2+ /Eu3+ , both the 4f → 5d transitions of Eu2+ and sharp emissions assigned to 5 D0 → 7 FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+ were observed. In addition, the results also reveal that the amount of ZrO2 affects the crystal structure, the self-reduction process and further influences the relative intensity of Eu2+ /Eu3+ in all samples. Therefore, the diverse emission colors can be obtained and modulated by controlling the content of ZrO2 . The highlight of this work is that the white light emission is observed, when x is 0.4, 0.6, 0.8 and 1, respectively.