Design, luminescence and energy transfer of single-phased color-tunable YNbO: Bi, Eu phosphor for UV pumped white light-emitting diodes.

Single-phased white light-emitting YNbO: Bi, Eu phosphors were synthesized by conventional solid-state reaction. YNbO: Bi phosphor exhibits a broad excitation band ranging from 220 to 360 nm and a blue light emission band peaking at 457 nm, originating from the P-S transition of Bi, whereas YNbO: Eu phosphor exhibits the typical red emission aroused from the D → F, D → F, D → F, D → F transitions of Eu. Under the excitation at 330 nm, the YNbO: Bi, Eu exhibits both the blue emission band of Bi and the red emission of Eu due to the energy transfer from Bi to Eu ions. By tuning the Bi/Eu ratio via the energy transfer, the emission hue of YNbO: Bi, Eu varied from blue (0.16, 0.18) to white (0.33, 0.24) and eventually to red (0.62, 0.33). The mechanism of energy transfer from a sensitizer Bi to an activator Eu in YNbO: Bi, Eu phosphors was demonstrated to be an exchange interaction. [ABSTRACT FROM AUTHOR]